Information storage system capable of recording and playing back a plurality of still pictures

ABSTRACT

An information storage medium capable of recording and playing back still picture information is provided with a first information unit having one still picture information, and a first group unit which is composed of a set of first information units, and has a plurality of pieces of still picture information having different contents. Information is recorded in the first group unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 10-192063, filed Jul. 7, 1998,the contents of which are herein incorporated by reference. Thisapplication is a divisional of U.S. patent application Ser. No.10/076,284 (filed Feb. 19, 2002), now U.S. Pat. No. 6,907,186 which is adivisional of U.S. patent application Ser. No. 09/630,430 (filed Aug. 1,2000) now U.S. Pat. No. 6,360,056, which is a divisional of U.S. patentapplication Ser. No. 09/348,267 (filed Jul. 7, 1999) now U.S. Pat. No.6,353,702, the entire contents of all of which are herein incorporatedby reference.

BACKGROUND OF THE INVENTION

The present invention relates to an information storage medium capableof recording and playing back a plurality of still pictures, a recordingmethod and apparatus therefor, and a playback method and apparatustherefor.

Recently, digital cameras have been prevalently used as media forrecording still image information as digital information. In a DVD thatrecords and plays back video information as digital information, menupictures and the like are displayed as still pictures.

In a digital camera, individual sensed still pictures are stored asdifferent files. When each still picture information is saved as anindependent file, the following problems remain unsolved.

a] Since still pictures are not grouped by similarity of contents orcloseness of image sensing times, it becomes troublesome to manage andsearch individual still pictures.

b] As an example of troublesome management of still pictures, differentfiles must be opened to check the contents of each still pictureinformation, resulting in cumbersome contents checking.

c] When a plurality of pieces of still picture information are to beprocessed in a recording/playback DVD disc, which assures compatibilityand continuity with a DVD Video disc to some extent, compatibility andcontinuity with the DVD Video disc cannot be maintained.

BRIEF SUMMARY OF THE INVENTION

Therefore, the present invention has the following objects:

A) an improvement associated with the recording format upon recordingstill picture information on an information storage medium;

B) an improvement associated with the data structure of managementinformation for still picture information recorded on an informationstorage medium;

C) an improvement associated with an information recording/playbackapparatus which records still picture information and its managementinformation on an information storage medium; and

D) an improvement associated with an information playback apparatus forplaying back still picture information and its management informationrecorded on an information storage medium.

More specifically:

A) It is an object of the present invention to provide a recordingformat and a data structure of management information, which are usedfor processing a plurality of pieces of still picture information whileassuring data compatibility and continuity of the recording format andmanagement information with a general video scheme of arecording/playback DVD disc that assures compatibility and continuitywith a DVD Video disc to some extent, and an informationrecording/playback apparatus that can implement such recording formatand data structure.

B) It is another object of the present invention to provide a recordingformat and data structure of management information, which allows easymanagement and search of a plurality of pieces of recorded still pictureinformation, and an information recording/playback apparatus that canimplement such recording format and data structure.

C) It is still another object of the present invention to provide aninformation playback apparatus which allows high-speed access to aninformation storage medium that records a plurality of pieces of stillpicture information so as to continuously display a plurality of piecesof still picture information (continuity upon playback).

In order to achieve the above objects, a plurality of pieces of stillpicture information are grouped and recorded on an information storagemedium, thus continuously recording the plurality of pieces of stillpicture information. In the group of the plurality of pieces of stillpicture information, at least two still pictures are continuouslyrecorded at neighboring locations on the information storage medium.

Also, management information that pertains to the grouped informationcontains map information, which records information which pertains toeach still picture information (e.g., the recording address of eachstill picture information on the information storage medium).

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIGS. 1A to 1F are views for explaining the data structure of aninformation recording medium according to an embodiment of the presentinvention;

FIG. 2 is a view for explaining the directory structure of data filesstored in a data area on the medium shown in FIGS. 1A to 1F;

FIGS. 3A to 3J are views for explaining the data structure in an AV fileshown in FIG. 2;

FIG. 4 is a view for explaining an example of the sequence (recordinglocation) when a video object VOB of AV file data is recorded on themedium shown in FIG. 1;

FIG. 5 is a view for explaining the data structure in an allocation maptable;

FIG. 6 is a view for explaining the data structure in program chaincontrol information (e.g., user-defined PGC information table UD_PGCIT);

FIGS. 7A and 7B are views for explaining playback examples of videoinformation (cell information) based on program chain PGC;

FIG. 8 is a view for explaining the data structure of managementinformation (video title set information VTSI or management informationRTR_VMGI for video real-time recording);

FIGS. 9A to 9F are views for explaining the order of sequence of videoobject VOBs according to video object information (M_VOBI for a movingpicture or S_VOGI for a still picture);

FIGS. 10A to 10L are views for explaining the recording format of apicture object/audio object for a still picture;

FIG. 11 shows a screen display example of picture object data (stillpicture) played back from the medium shown in FIG. 1;

FIG. 12 is a view for explaining the data structure of information thatpertains to a video object in a still picture AV file (S_AVFIT) shown inFIG. 8;

FIG. 13 is a view for explaining the data structure (the data structurethat pertains to S_VOGI in FIG. 9) of a video object unit VOBU in apicture object;

FIGS. 14A to 14G are views for explaining the relationship between thedata structure in a VOB upon continuously recording still pictures, andthe designation contents of a corresponding cell;

FIG. 15 is a view showing an example of the correspondence among thedata structure cell playback information (cell information S_CI for astill picture) of a picture object, the contents of the cell playbackinformation, and components shown in FIGS. 14A to 14G;

FIG. 16 is a view showing an example of another data structure of cellplayback information (,cell information CI) of a picture object;

FIG. 17 is a view for explaining the data structure of part_of_title(chapter) information that pertains to a still picture in AV fileinformation (S_AVFI) for a still picture;

FIG. 18 is a view for explaining the data structure of a VOB map of thepicture object shown in FIG. 17;

FIG. 19 is a block diagram showing an example of the arrangement of adigital video recording/playback apparatus (RTR video recorder) usingthe medium (a DVD_RTR disc capable of recording/playing back a video inreal time) shown in FIG. 1;

FIG. 20 is a flow chart for explaining the sequence for recording one ormore still pictures on the medium shown in FIG. 1;

FIG. 21 is a flow chart showing the sequence when audio information isafter-recorded on the medium shown in FIG. 1;

FIG. 22 is a flow chart showing the sequence when one or more stillpictures are played back from the medium shown in FIG. 1;

FIG. 23 is a view for explaining the data structure of controlinformation/navigation data (RTR_VMG) shown in FIG. 1E or FIG. 8;

FIG. 24 is a view for explaining the contents of still picture cellinformation (S_CI) shown in FIG. 23;

FIG. 25 is a view for explaining the contents of still picture cellgeneral information (S_C_GI) shown in FIG. 24;

FIG. 26 is a view for explaining the contents of each still picture cellentry point (S_C_EPI) shown in FIG. 24;

FIG. 27 is a view for explaining the contents of still pictureadditional audio file information (S_AAFI) shown in FIG. 12;

FIG. 28 is a view for explaining the contents of S_AAG generalinformation (S_AAG_GI) shown in FIG. 27;

FIG. 29 is a view for explaining the contents of an additional audioentry (AA_ENT) shown in FIG. 27;

FIG. 30 is a view for explaining the contents of still picture VOB groupgeneral information (S_VOG_GI) shown in FIG. 12;

FIG. 31 is a view for explaining the first example (type 1) of thecontents of a still picture VOB entry (S_VOB_ENT) shown in FIG. 12;

FIG. 32 is a view for explaining the second example (type 2) of thecontents of a still picture VOB entry (S_VOB_ENT) shown in FIG. 12;

FIG. 33 is a view for explaining the third example (type 3) of thecontents of a still picture VOB entry (S_VOB_ENT) shown in FIG. 12;

FIG. 34 is a view for explaining the fourth example (type 4) of thecontents of a still picture VOB entry (S_VOB_ENT) shown in FIG. 12;

FIG. 35 is a view for explaining the relationship between original PGCinformation (ORG_PGCI shown in FIG. 8 or 23) and a still picture videofile (RTR_STO.VRO shown in FIG. 2) when a still picture VOB alone isrecorded;

FIG. 36 is a view for explaining the relationship between original PGCinformation (ORG_PGCI) and a still picture additional audio part(RTR_STA.VRO shown in FIG. 2);

FIG. 37 is a view for explaining the relationship among a still pictureVOB, movie VOB, and original PGC information; and

FIG. 38 is a view for explaining a case wherein user-defined PGCInformation (FIG. 6) looks up a still picture VOB group.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be describedhereinafter with reference to the accompanying drawings.

[1] Outline of Data Structure on Information Storage Medium

The recording information contents (data structure) of informationrecorded on an information storage medium (Optical Disc or DVD_RTR disc1001) that can record and play back video information and musicinformation shown in FIG. 1A will be explained below.

The data structure of information recorded on the information storagemedium (optical disc 1001) is roughly divided, in the order from innerside 1006 in FIG. 1B, into:

lead-in area 1002 having an embossed data zone whose light reflectionsurface has an embossed pattern, a mirror zone whose surface is flat(mirror surface), and a rewritable data zone capable of informationrewriting;

volume & file manager information 1003 that records information which isrecorded on a rewritable data zone which can be recorded/rewritten bythe user, and pertains to the entire file or volume of audio & videodata;

data area 1004 made up of a rewritable data zone that can berecorded/rewritten by the user; and

lead-out area 1005 made up of a rewritable data zone capable ofinformation rewriting.

The embossed data zone of lead-in area 1002 records in advance:

information such as the disc type indicating a DVD-ROM, DVD-RAM, DVD-R,or the like, disc size, recording density, physical sector numbersindicating the recording start/end positions, and the like, whichpertain to the entire information storage medium;

information such as the recording power and width, erase power, playbackpower, and linear velocity upon recording and erasure, which pertain tothe recording/playback/erasure characteristics; and

information such as the manufacturing number and the like, which pertainto the manufacture of each information storage medium.

The rewritable data zone of each of lead-in and lead-out areas 1002 and1005 has a unique disk name recording field for each informationrecording medium, a test recording field (for confirmingrecording/erasure conditions), and a management information recordingfield that pertains to a defective field in data area 1004, and aninformation recording/playback apparatus can record information on thesefields.

Data area 1004 sandwiched between lead-in and lead-out areas 1002 and1005 can record both computer data and audio & video data, as shown inFIG. 1C. The recording order, each recording information size, and thelike of computer data and audio & video data can be arbitrarilydetermined. Locations where the computer data are recorded will bereferred to as computer data areas 1008 and 1010, and a location wherethe audio & video data are recorded will be referred to as audio & videodata area 1009 hereinafter.

As shown in FIG. 1D, the data structure of information recorded in audio& video data area 1009 contains:

anchor pointer for control information 1015: information indicating thestart location (start address) where control information 1011 isrecorded in audio & video data area 1009;

control information 1011: control information (corresponding to RTR.IFOshown in FIG. 2) required upon executing respective processes, i.e.,video recording (audio recording), playback, editing, and search;

video objects 1012: video recording information of video data contents;

picture objects 1013: still picture information such as still pictures,slide pictures, and the like;

audio objects 1014: audio recording information of audio data contents;

thumbnail objects 1016: information such as thumbnails used uponsearching for a location the user wants to watch or upon editing; and soon.

Video objects 1012, picture objects 1013, audio objects 1014, andthumbnail objects 1016 shown in FIG. 1D mean groups of informationclassified in units of contents (data contents). Hence, all pieces ofvideo information recorded on audio & video data area 1009 are containedin video objects 1012, all pieces of still picture information arecontained in picture objects 1013, all pieces of audio information arecontained in audio objects 1014, and all pieces of thumbnail informationused in video information management and search are contained inthumbnail objects 1016.

VOB (video object) 1403 shown in FIG. 3D (to be described later)indicates a cluster of information recorded in AV file (i.e., audio &video file) 1401, and has a definition different from that of videoobjects 1012 shown in FIG. 1D. Note that similar terms often have quitedifferent meanings.

Furthermore, as shown in FIG. 1E, the contents of control information1011 include:

AV data control information 1101: management information which managesthe data structure in video object 1012 or manages information thatpertains to the recording locations on optical disc 1001 as aninformation storage medium;

playback control information 1021: control information required uponplayback;

recording control information 1022: control information required uponrecording (video/audio recording);

edit control information 1023: control information required uponediting;

thumbnail control information 1024: management information that pertainsto thumbnails (thumbnail object) used to search for a location the userwants to watch in video data or to edit; and the like.

Note that Control information 1101 and playback control information 1021shown in FIG. 1E correspond to RTR.IFO shown in FIG. 2, and RTR_VMGshown in FIG. 23.

As shown in FIG. 1F, the data structure in AV data control information1101 shown in FIG. 1E is comprised of:

allocation map table 1105: information which pertains to address setupsalong the actual layout, identification of recorded/unrecorded areas,and the like on the information storage medium (optical disc 1001);

video title set information 1106: time information (corresponding toRTR_VMGI in FIG. 8) which indicates the overall information contents inAV file 1401 shown in FIG. 3A, and includes link information among VOBs,grouping information of a plurality of VOBs for management and search, atime map table, and the like;

video object information 1107: information (corresponding toM_AVFIT/S_AVFIT in FIG. 8 or S_AVFIT in FIG. 12) which indicatesinformation pertaining to each VOB in AV file 1401, and pertains toattribute (characteristic) information in units of VOBUs, and each VOBUcontained in the VOB;

PGC control information 1103: information (corresponding to PGCI in FIG.23) that pertains to a video information playback program (sequence);and

cell playback information 1108: information (corresponding to CI in FIG.23 or S_CI in FIG. 24) that pertains to the data structure of a basicvideo information unit upon playback.

The aforementioned contents are a brief explanation of the datastructure shown in FIGS. 1A to 1F. Some additional explanations of eachinformation will be given below.

Volume & file manager information 1003 records:

information that pertains to the entire volume;

the number of files of contained PC data, and the number of filesassociated with AV data;

information associated with recording layer information and the like.

Especially, as the recording layer information, information 1003records:

the number of layers that form a disc (e.g., a single RAM/ROMtwo-layered disc has two layers, a single ROM two-layered disc also hastwo layers, and n single-sided discs are counted as n layers);

a logical sector number range table (capacity in units of layers)assigned in units of layers;

the characteristics (e.g., a DVD-RAM disc, a RAM section of a RAM/ROMtwo-layered disc, a CD-ROM, a CD-R, and the like) in units of layers;

an assigned logical sector number range table (including rewritable areacapacity information of each area) in units of zones on a RAM area ofeach layer; and

unique ID information of each layer (e.g., to find out a disc exchangeevent in a multi-disc pack). With this information, continuous logicalsector numbers can be set even for a multi-disc pack or RAM/ROMtwo-layered disc to handle such discs or disc as a single, large volumespace.

Playback control information 1021 records:

information that pertains to a playback sequence which combines PGCs;

information (a sequence for continuously playing back all recordedcells) indicating a pseudo recording location considering theinformation storage medium as a single tape like a VTR or DVC inrelation to the above information;

information that pertains to simultaneous playback on a plurality ofscreens having different kinds of video information;

search information: information which records cell IDs corresponding tosearch categories, and a table of start times in a given cell, andallows the user to select and directly access the video information ofinterest; and the like.

Recording control information 1022 records:

program reservation recording information and the like.

Furthermore, edit control information 1023 records:

special edit information in units of PGCs (corresponding time setupinformation and special edit contents are described as EDL information);and

file conversion information (which converts a specific field in an AVfile into a file such as an AVI file that can undergo special editing ona PC, and designates the storage location of the converted file).

Thumbnail control information 1024 describes:

management information that pertains to thumbnail objects 1016(designation information of the recording location of each thumbnailpicture in audio & video data area 1009 and a VOB or cell associatedwith each thumbnail picture, location information in a VOB or cellassociated with each thumbnail picture, and the like (the VOB and cellwill be explained in detail later upon explaining the contents of FIGS.3A to 3J)).

The directory structure of data files in the data area will be describedbelow.

All pieces of information are recorded in units of files in data area1004 in FIG. 1B, and the relationship among data files is managed by thedirectory structure shown in FIG. 2.

Referring to FIG. 2, a plurality of subdirectories 1451 are containedwithin root directory 1450 to allow easy classification in units ofrecorded file contents. In the embodiment shown in FIG. 2, data filesthat pertain to computer data recorded on computer data areas 1008 and1010 shown in FIG. 1C are recorded under subdirectory 1457 for computerdata storage, and audio & video data recorded on audio & video data area1009 are recorded under rewritable video title set RW_VTS 1452. On theother hand, upon copying video information recorded on a DVD Video discor (DVD Audio disc) to the disc shown in FIG. 1A, data are copied undervideo title set VIDEO_TS 1455, and audio title set AUDIO_TS 1456.

Control information 1011 in FIG. 1D is recorded as a single file forrecording/playback video management data. In the embodiment in FIG. 2,that information has file name RW_VIDEO_CONTROL.IFO (or real timerecording information; abbreviated as RTR.IFO). Furthermore, identicalinformation is also recorded as backup information with file nameRW_VIDEO_CONTROL.BUP.

In the embodiment shown in FIG. 2, all of video objects (RTR_MOV.VRO)1012, picture objects (RTR_STO.VRO) 1013, audio objects (RTR_STA.VRO)1014, and thumbnail objects 1016 are recorded as single AV file 1401(the file name in the embodiment in FIG. 2 is RW_OBJECT.OB).

Rewritable additional information 1454 (not shown in FIGS. 1A to 1F)that can be used upon recording/playing back video information can besimultaneously recorded. That information is recorded as a single file,which has file name RW_ADD.DAT (corresponding to S_AA_STI/S_AAFI in FIG.12 or AA_ENT in FIG. 27) in the embodiment in FIG. 2.

FIGS. 3A to 3J show an example of the data structure in an AF file. Asshown in FIG. 3B, entire. AV file 1401 forms single VTS (video titleset) (or RTR movie object RTR_MOV.VRO) 1402. VTS 1402 contains a groupof a plurality of VOBs (video objects) 1403, 1404, and 1405, which areseparated into a plurality of part_of_titles (or a plurality ofchapters) 1407 and 1408 in accordance with the contents of audio & videodata and the order of information recorded in AV file 1401.

VOBs 1403, 1404, and 1405 in FIG. 3D are defined as sets of audio &video data recorded in AV file 1401, and have definition contentsdifferent from video objects 1012 shown in FIG. 1D that primarily servethe purposes of classification items of video information/still pictureinformation/audio information/thumbnail information and the like. Hence,VOBs 1403, 1404, and 1405 in FIG. 3D record not only informationclassified into video objects 1012, but also information classified intopicture objects 1013, audio objects 1014, and thumbnail objects 1016, asshown in FIG. 10.

Associated VOBs are grouped into a plurality of PTTs (part_of_titles orchapters) 1407 and 1408 based on information contents recorded in VOBs1403, 1404, and 1405. That is, PTTs 1407 and 1408 are formed as sets ofone or a plurality of VOBs. In the embodiment shown in FIG. 3C, PTT 1408is formed by two VOBs, i.e., VOBs 1404 and 1405, and PTT 1407 is formedby one VOB 1403 alone.

Minimum basic units of video information are called VOBUs (video objectunits) 1411 to 1414, and data in VOBs 1403 to 1405 are formed as sets ofVOBUs 1411 to 1414, as shown in FIG. 3E.

MPEG1 or MPEG2 is prevalently used as the video information compressiontechnique in VOBs 1403 to 1405. MPEG segments video information intogroups called GOPs in 0.5-sec increments, and compresses videoinformation in units of GOPs. Video information compression units ofVOBUs 1411 to 1414 are formed to have nearly the same size as that ofGOP in synchronism with GOP.

Furthermore, VOBUs 1411 to 1414 are recorded while being segmented intosectors 1431 to 1437 in units of 2,048 bytes. Sectors 1431 to 1437record raw video information, sub-picture information, audioinformation, and dummy information in units of packs in the form of packstructures, i.e., V_PCKs (video packs) 1421, 1425, 1426, and 1427,SP_PCK (sub-picture pack) 1422, A_PCK (audio pack) 1423, and DM_PCK(dummy pack) 1424. Each dummy pack size is 2,048 bytes. However, sinceeach pack has a 14-byte pack header at the start of it, the informationsize recorded in each pack is 2,034 bytes.

Note that DM_PCK (dummy pack) 1424 is inserted for the purposes of:

addition of information to be additionally recorded after videorecording (for example, memo information indicating that after-recordinginformation is inserted into an audio pack and replaced by a dummy packis inserted in sub-picture information (a sub-picture pack) and isreplaced by a dummy pack).

The recording area of a DVD-RAM (DVD_RTR) disc as an example of theinformation storage medium (optical disc 1001) shown in FIG. 1A issegmented into a plurality of sectors. 2,048-byte data can be recordedper sector. In this DVD-RAM disc, recording/playback is done in units ofsectors (2,048 bytes). Hence, when a DVD-RAM disc is used as theinformation storage medium (optical disc 1001), the respective packs arerecorded in units of sectors 1431 to 1437, as shown in FIG. 3F.

As shown in FIGS. 3B and 3D, VTS (video title set or RTR_MOV.VRO) 1402is formed by a sequence of all VOBs 1403 to 1405 in AV file 1401. Bycontrast, a playback sequence described in playback control information(pack control information) 1021 can designate an arbitrary range in anarbitrary VOB, and can play it back in an arbitrary playback order.

Basic video information units upon playback are called cells 1441, 1442,and 1443. Each of cells 1441, 1442, and 1443 can designate an arbitraryrange in an arbitrary VOB, but cannot make designation across aplurality of VOBs (one cell cannot set a range by linking a plurality ofVOBs).

In the embodiment shown in FIG. 3G, cell 1441 designates one VOBU 1412in VOB 1403, cell 1442 designates whole VOB 1404, and cell 1443designates the range of only a specific pack (V_PCK 1427) in VOBU 1414.

Information indicating a video information playback sequence is set byPGC (program chain) 1446, and is described by designating a single cellor by link information of a plurality of cells. For example, in theembodiment shown in FIG. 3H, PGC (program chain) 1446 forms a playbackprogram as a link of cells 1441, 1442, and 1443 (the relationshipbetween the cell and PGC will be described in detail later).

VOBU 1403 in FIG. 3D can contain not only video information but alsoaudio information. In this case, VOBU 1411 that forms VOB 1403 containsV_PCK 1421 and SP_PCK 1422 that construct a video part, and A_PCK 1423and DM_PCK (for after recording) 1424 that construct an audio part.

The video part is formed by a sequence header and GOP header composed ofsome contents on the start side of V_PCK, MPEG I-picture composed of thecontents of a V_PCK group, a sequence end code composed of some contentson the end side of V_PCK, and sub-picture unit SPU composed of thecontents of SP_PCK.

The audio part contains audio data to be played back in synchronism withstill picture playback using I-picture of the video part, and iscomprised of one or more audio frames.

The contents of allocation map table 105 in FIG. 11F will be describedbelow with reference to FIG. 4.

As described above, the recording area of the DVD-RAM disc is segmentedinto a plurality of sectors, and logical sector numbers (LSNs) arecontinuously assigned in ascending order from the inner side.

A case will be examined below wherein video information is recorded indata area 1004 of the information storage medium (optical disc 1001) inthe following sequence.

1. An area for recording AV file 1401 is assured in a continuous area(a<g) from logical sector numbers (LSN) a+1 to g in data area 1004 onthe information storage medium (optical disc 1001).

2. Data of VOB#1 1461 is recorded in a continuous area (b<c) fromlogical sector numbers (LSN) b+1 to c in the area for recording AV file1401.

3. Data of VOB#2 1462 is recorded in a continuous area (d<e) fromlogical sector numbers (LSN) d+1 to e in the area for recording AV file1401.

As a result of the above processes in 1. to 3., three unrecorded areas“from a+1 to b”, “from c+1 to d”, and “from e+1 to g” in logical sectornumbers (LSN) remain in AV file 1401. When video information of VOB#3with a large data size is recorded in these unrecorded areas, thefollowing processes are required.

4. Data of VOB#3 is segmented into a plurality of data in correspondencewith the unrecorded area sizes in the area for recording AV file 1401.

5. First segmented data 1463 of VOB#3 is recorded in a continuous area(a<b) from logical sector numbers (LSN) a+1 to b.

6. Next segmented data 1464 of VOB#3 is recorded in a continuous area(c<d) from logical sector numbers (LSN) c+1 to d.

7. Last segmented data 1465 of VOB#3 is recorded in a continuous area(f<g) from logical sector numbers (LSN) f+1 to g.

As a result, unrecorded area 1460 “from e+1 to f” in logical sectornumbers (LSN) remains in AV file 1401. FIG. 4 shows the distribution ofphysical recorded positions of VOBs in AV file 1401 as a result of theabove processes in 1. to 7.

As can be seen from the above description, when data in AV file 1401 ispartially erased or when new data is additionally recorded in anunrecorded area in AV file 1401, single VOB data must be segmented andrecorded at a plurality of locations like data 1463, 1464, and 1465 ofVOB#3.

Allocation map table 1105 shown in FIG. 1F shows information indicatingthe distribution of physical positions of identical data distributed andrecorded in AV file 1401 in units of VOBs. FIG. 5 shows the informationcontents of allocation map table 1105 taking the data allocation shownin FIG. 4 as an example. Allocation map table 1105 is comprised ofdistribution information 1621 of positions of unrecorded areas, and aplurality of pieces of distribution information 1622, 1623, and 1624 ofpositions of recorded data in units of VOBs.

A cluster of data units having continuous logical sector numbers in eachVOB will be defined as an “extent”. In the embodiment shown in FIG. 4,data of VOB#3 are recorded as three extents. In the above example, sincean area from logical sector numbers a+1 to b has continuous logicalsector numbers, this area forms “extent#γ 1473”. That is, the recordingpositions of the data of VOB#3 are distributed to three locations, i.e.,extent#γ 1473, extent#δ 1474, and extent#ε 1475.

The position distribution information that pertains to unrecorded areasor each VOB in allocation map table 1105 shown in FIG. 5 records thenumber 1601, 1602, 1603, or 1604 of extents at its first position. Afterthat, first address 1606, 1607, 1608, 1609, 1610, or 1611 and size 1614,1615, 1616, 1617, 1618, or 1619 of each extent are recorded. The firstaddress is expressed by a “differential number” (or relative sectornumber) from the first logical sector number of AV file 1401. When eachfirst address is expressed by a differential number, if the entirecontents of AF file 1401 are transplanted to another informationrecording medium, information in allocation map table 1105 need not bechanged, thus improving file portability. In FIG. 5, the extent size isexpressed by the number of sectors. The extent size may be expressed bythe last address of each extent in place of the number of sectors inFIG. 5.

In the DVD-RAM disc (DVD_RTR disc) format, information indicating aphysical address on the information storage medium (optical disc 1001)is called a physical sector number (PSN), the entire address used by thefile system is called a logical sector number (LSN), and an addressdefined on the file system in data area 1004 in FIG. 1A is called alogical block number (LBN), thus distinguishing PSN, LSN, and LBN fromeach other. However, if this convention is always observed, thedescription becomes complicated. For this reason, FIG. 5 uses anexpression based on logical sector numbers (LSN) for the sake of easyunderstanding.

The contents of playback control information 1021 will be describedbelow with reference to FIGS. 6 to 7B. PGC (program chain) controlinformation 1103 in playback control information 1021 has the datastructure shown in FIG. 6, and the playback order is determined by PGCand cells. PGC is a unit that designates the playback order of cells andexecutes a given playback sequence. On the other hand, each cellindicates a playback period that designates playback data in each VOB bythe start and end addresses, as shown in FIGS. 3D to 3F.

PGC control information 1103 is composed of PGC information managementinformation 1052, one or more search pointers 1053 and 1054 of PGCinformation, and a plurality of pieces of PGC Information 1055, 1056,and 1057.

PGC information management information 1052 contains information (numberof PGC information) indicating the number of PGCs. Each of searchpointers 1053 and 1054 of PGC Information points to the first positionof each PGC information, and allows an easy search. Each PGC information1055, 1056, or 1057 consists of PGC general information 1061, one ormore pieces of program information (PGI#m), one or more cell IDs (orCI_SRP#m), and one or more pieces of cell information (CI#m). PGCgeneral information (PGC_GI) 1061 contains information (number of cellplayback information) indicating the playback time of PGC and the numberof cells. Or PGC_GI 1061 may contain information indicating the numberof programs (PGs) and the number of search pointers (CI_SRP) of cellinformation.

As shown in FIG. 7A, playback data are designated as a playback periodin units of cells from cell-A to cell-F, and PGC information is definedin each PGC.

1. PGC#1 exemplifies a case wherein it is composed of cells thatdesignate a continuous playback period, and its playback order iscell-A→cell-B cell→cell-C.

2. PGC#2 exemplifies a case wherein it is composed of cells thatdesignate an intermittent playback period, and its playback order iscell-D→cell-E→cell-F.

3. PGC#3 exemplifies a case wherein playback can be done intermittentlyirrespective of the direction of playback or repetitive playback, andits playback order is cell-E→cell-A→cell-D→cell-B→cell-E.

Control information (RTR.IFO) 1011 shown in FIG. 1D or 2 containsnavigation data RTR_VMG (real time recording video manager)corresponding to control information 1101 and control information 1021,as shown in FIG. 1E. This RTR_VMG contains video title set informationVTSI (or information RTR_VMGI of RTR_VMG) 1106, as shown in FIG. 1F.

This information (RTR_VMGI) 1106 contains information used upon playingback a sequence of VOBs 1403, 1404, 1405, . . . , shown in FIG. 3D.

The data structure and contents of RTR_VMG in FIG. 1E (or RTR.IFO inFIG. 2) will be explained below with reference to FIG. 8.

As shown in FIG. 8, navigation data RTR_VMG (control informationRTR.IFO) is comprised of RTR video manager information (RTR_VMGI), amovie AV file information table (M_AVFIT), a still picture AV fileinformation table (S_AVFIT), original PGC information (ORG_PGCI), auser-defined PGC information table (UD_PGCIT), a text data manager(TXTDT_MG), and a table (MNFIT) of information that pertains to themanufacturer.

RTR_VMGI contained in this RTR_VMG corresponds to video title set (VTS)information 1106 shown in FIG. 1F.

This information (RTR_VMGI) 1106 contains VTS general information 1751,VOB sequence information 1752, PTT information 1753, and VTS time maptable 1754, as shown in FIG. 8.

Put otherwise, this information (RTR_VMGI) 1106 contains a play listsearch pointer table (PL_SRPT) corresponding to VOB sequence information1752, and a video manager information management table (VMGI_MAT)corresponding to VTS general information 1751.

Table PL_SRPT contains information 1756 indicating the number of VOBs inVTS (or the number of play list search pointers and the end address ofPL_SRPT), information 1757 indicating the ID of the first VOB in a VOBsequence (or first play list search pointer PL_SRP#1), information 1758indicating the ID of the second VOB in the VOB sequence (or second playlist search pointer PL_SRP#2), and the like.

Each play list search pointer (PL_SRP) contains information (PL_TY)indicating the type of a play list, PGC number information (PGCN)corresponding to this play list, information (PL_CREATE_TM) indicatingthe date of creation of this play list, information (PRM_TXTI) ofprimary text associated with this play list, number information(IT_TXTI_SRPN) of a search pointer of item text used in this play list,and thumbnail pointer information (THM_PTRI) indicating a thumbnailpicture corresponding to the recording contents of this play list.

The table (PL_SRPT) that contains these pieces of information 1756,1757, 1758, . . . corresponds to VOB sequence information 1752 containedin VTSI (RTR_VMGI) 1106.

The contents of VTSI (RTR_VMGI) 1106 can be summarized as follows.

That is, as shown in FIG. 8, the data structure in video title setinformation (or RTR_VMGI) 1106 records:

video title set general information 1751 . . . This information pertainsto general contents of a video title set (or RTR data in AV file 1401 inFIG. 2);

video object sequence information 1752 . . . In the data structure shownin FIGS. 3A to 3J, serial numbers are set for all VOBs in video titleset 1402 (=AV file 1401). This information describes serial numberinformation of VOBs according to this sequence;

part_of_titles information 1753 . . . . Object data recorded in AV file1401 are grouped in units of associated data for the purpose of eachdata management and search, and video title names are set in units ofgroups. The group (part_of_title) is formed of a set of VOBs. Thisinformation describes VOB information contained in each part_of_title;and

video title set time map table 1754 . . . . This information pertains toVOBU position information at specific time intervals according to thevideo object sequence in relation to VOBs which are classified intovideo objets 1012 and audio objects 1014 in video title set 1402.

The detailed data structure in video object sequence information 1752 isshown on the right side in FIG. 8. That is, the total number 1756 ofVOBs (or PL_SRPTI) contained in the video title set is recorded at thefirst position. After that, VOB_IDs (or PL_SRP#1, PL_SRP#2, . . . ,PL_SRP#n) 1757, 1758, . . . corresponding to serial numbers are recordedin the sequence (video object sequence) order.

The sequence indicated by video object sequence information 1752 can bearbitrarily set by the user or information recording/playback apparatusside in, e.g., “the recording order to AV file 1401 (ascending order ofrecording time)”, “the recording allocation order on the informationstorage medium (optical disc) shown in FIG. 4”, “the VOB size order”,and the like. By sequentially determining the order of all VOBs in VTS(video title set) 1402, a user interface similar to a VTR that recordsvideo data on a single table can be provided.

For example, the following processes can be done using video objectsequence information 1752:

to search for a scene the user wants to watch by fast-forwarding (FF) orrewinding (FR) a tape;

to confirm the entire recording contents by fast-forwarding (FF) thetape; and

to search for an unnecessary recorded scene by fast-forwarding (FF) orrewinding (FR) the tape, and to overwrite new video information on thatscene.

The information contents of video object sequence information 1752 shownon the right side in FIG. 8 will be explained below with reference toFIGS. 9A to 9F. A case will be examined first wherein VOB#1 to VOB#3 arerecorded to have the allocation order on the information storage medium(optical disc) shown in FIG. 4, and this recording is done in the orderof 1. to 7. described in “description of allocation map table contents”.FIG. 9C shows the sequence order which is set for these data in “therecording order to AV file 1401 (ascending order of recording time)”.Compared to FIG. 4, the allocation order from extent#α 1471 to extent#ζ1470 has changed. “First VOB_ID 1757 in the video object sequence” shownin FIG. 8 designates “VOB#1 1461” in FIG. 9C, and “second VOB_ID 1758 inthe video object sequence” designates “VOB#2 1462” in FIG. 9C.

FIG. 9F shows another embodiment designated by video object sequenceinformation 1752. VOB#A 1771 and VOB#B 1772 belong to (are classifiedto) video objects (movie VOB information M_VOBI#) 1012, VOB#C 1773,VOB#F 1776, and VOB#G 1777 to audio objects 1014, and VOB#D 1774 andVOB#E 1775 to picture objects (still picture VOB group informationS_VOGI#) 1013. In this way, the sequence order can be designatedindependently of the VOB types. In FIG. 9F, VOBs (VOB#H 1778 and VOB#I1779) that belong to thumbnail objects 1016 are set at the end of thesequence.

The recording format upon recording still picture information on theinformation storage medium (optical disc 1001) shown in FIG. 1A will beexplained below.

Still picture information or audio information (information thatadditionally records audio data of a comment for each still pictureinformation by after recording) to be added later to still pictureinformation are recorded at a location of picture objects 1013 or audioobjects 1016 in FIG. 1D. For example, the format is designed to becapable of continuously recording a plurality of, still picturesassuming that a plurality of still pictures sensed by a digital cameraare recorded on the information storage medium (optical disc 1001) atone time. In order to allow to continuously record a plurality of stillpictures, the format is designed to record at least two still picturesat neighboring locations on the information storage medium (optical disc1001).

A still picture or audio information to be added to the still picturefollows the data structure shown in FIGS. 3A to 3J to attain formatcontinuity and matching with video information (video objects 1012). InMPEG1 or MPEG2 as one type of recording format (video informationcompression format) of video information, compressed information for onecorresponding video frame is present at the start position of theaforementioned GOP in the form of “I-picture”.

As shown in FIGS. 10C and 10I, input still pictures are converted intoI-pictures 1706, 1707, 1708, and 1709 using the MPEG1 or MPEG2compression technique, and these I-pictures are recorded on theinformation storage medium (optical disc 1001) while being stored inV_PCKs (video packs) 1661, 1662, 1663, 1668, 1669, 1670, 1671, 1672,1673, and 1674.

As described above, on the DVD-RAM (DVD_RTR) disc, each V_PCK (videopack) is recorded in units of sectors each having a recording size of2,034 bytes (see FIG. 3F) [one sector size is 2,048 bytes, but sinceeach pack has a 14-byte pack header, the recording size per pack is2,034 bytes].

When the I-picture size corresponding to one still picture informationis smaller than an integer multiple of 2,034 bytes, dummy information1704 is recorded in that short field. In this way, each I-picture canjust fall within an integral number of sectors.

Since I-picture size 1808 in each VOBU is recorded in information of aVOBU map for picture objects, as shown in FIG. 13 (to be described indetail later), the start position of dummy information 1704 in V_PCK(video pack) 1670 can be determined. Hence, the contents of dummyinformation 1704 can be arbitrarily set.

For example, as the contents of dummy information 1704, for example, asequence end code (or a packet header with stream ID=0×be) can berecorded as specific information which can be specified as dummy when itis played back, in addition to padding data with all “0”s or all “1”s.

Note that allocation of I-pictures is omitted in FIGS. 10F and 10L, butthe data has the same structure as in FIGS. 10C and 10I.

For example, when a still picture is sensed using a digital camera, andsome comment is to be directly added by handwriting on that sensedpicture (still picture), the information of the comment contents can berecorded as a sub-picture stream in SP_PCKs (sub-picture packs) 1681,1682, and 1683 in addition to the still picture recorded as I-picture inV_PCK. Upon playback, I-picture still picture information in V_PCK andsub-picture information in SP_PCKs are displayed to overlap each other.

Audio information that stores a comment for each still picture as audiodata is recorded in A_PCKs (audio packs) 1691 to 1702.

In this manner, V_PCKs 1661 to 1674, SP_PCKs 1681 to 1684, and A_PCKs1691 to 1702 are gathered in units of associated still pictures, and aregrouped in units of VOBUs (video objects for picture objects) 1641 to1650. Hence, in the format shown in FIGS. 10A to 10L, each still pictureforms one VOBU.

In the embodiment shown in FIGS. 10A to 10L, V_PCKs and SP_PCK arerecorded before A_PCKs in each VOBU. As a result, the individual packsare separated in each VOBU, and information in each pack can be easilymanaged.

However, the embodiment of the present invention is not limited to theaforementioned limitation, and allows to allocate A_PCKs, V_PCKs, andSP_PCKs in an arbitrary order as in the recording format in videoobjects 1012.

Furthermore, V_PCKs 1664 having still picture information recorded inthe I-picture format must be allocated in single VOBU 1642, but A_PCK(1694) that records part of audio information associated with VOBU 1642can be allocated in next VOBU 1643.

As will be described later with reference to. FIG. 13, continuous audioinformation can be separated in correspondence with each still imageusing information of E_PTM (presentation terminating time) 1814 of audioinformation recorded in VOBU map 1738 for picture objects.

As the format that can continuously record a plurality of pieces ofstill picture information, the format structure shown in FIGS. 10A to10L permits the following two different methods and mixed recording byboth the methods.

1) One VOB is formed of a plurality of VOBUs.

2) One VOB has only one VOBU, and VOBs each of which records a singlestill picture are grouped to construct VTT (video title).

FIGS. 10D to 10L show the former format structure 1), and FIGS. 10A to10C show the latter format structure 2). In the former format structure1), FIGS. 10D to 10F show the basic structure. As special examples,FIGS. 10G to 10I show a structure which does not include any audioinformation (A_PCK), and FIGS. 10J to 10L show a structure which doesnot include any original still picture (V_PCK). After a plurality ofpieces of still picture information which do not contain any audioinformation and are sensed by a digital camera are recorded on theinformation storage medium (optical disc 1001) at one time, the user mayoften input memo data (additionally recorded as SP_PCK) or audio data(additionally recorded as A_PCK) for each still picture while observingthe plurality of pieces of recorded still picture information. In suchcase, efficient editing and recording can be done when only additionaldata (memo and audio data) are gathered to form and record a VOBdifferent from that which records original still picture information, onthe information storage medium (optical disc 1001). When additional dataare recorded as another VOB, the contents of a VOB that records originalstill picture information need not be changed. In this fashion, therecording format in VOB 1634 that gathers only additional data (memo andaudio data) for the purpose of easy editing for still pictureinformation has a structure (which contains only A_PCK and SP_PCKwithout any V_PCK) similar to that shown in FIGS. 10J to 10L.

Note that I-picture data shown in FIGS. 10C and 10I corresponds to thatshown in FIG. 3J, and dummy data shown in FIGS. 10C and 10I correspondsto dummy pack DM_PCK shown in FIG. 3F.

Also, video pack V_PCK, sub-picture pack SP_PCK, and audio pack A_PCKshown in FIGS. 10A to 10L respectively correspond to V_PCK, SP_PCK, andA_PCK shown in FIG. 3F.

Dummy pack DM_PCK shown in FIG. 3F or FIGS. 10C and 10I can beappropriately used for the purpose of audio data after recording and thelike. For example, when the size of an encoded I-picture data clusterdoes not match an integer multiple of the block size (16 sectors/32kbytes) of an error correction code (ECC) that uses a product code,DM_PCK can be added to this data cluster as needed so that the I-picturedata cluster size matches an integer multiple of 32 kbytes.

When the cluster sizes of all I-picture data that form still picturesare matched with an ECC block unit (an integer multiple of 32 kbytes) byadding DM_PCK, the following merits are obtained.

For example, when one of a plurality of still pictures that have beencontinuously recorded on the medium shown in FIG. 1 is replaced byanother still picture (or erased), since the still picture (I-picture)to be replaced (or erased) has an ECC block unit even if it has a sizedifferent from the original still picture, the ECC block units ofI-pictures which are not replaced (not erased) are not disturbed.

For this reason, even when one of still pictures is replaced by anotherstill picture (or erased), ECC coding of I-pictures which are notreplaced (not erased) need not be redone. Since ECC coding need not beredone, the operation speed of an RTR recorder can be improvedaccordingly, and recorded still pictures can be smoothly edited (toreplace or erase some still pictures).

However, when the size of a still picture to be replaced is larger thanthe original still picture size, the still picture data to be replacedis partially recorded at another recording location. That is, thereplaced still picture gets fragmented. When the seek speed of a discdrive that reads out data from the medium shown in FIG. 1 is low,playback of the fragmented still picture requires a relatively longperiod of time. Hence, when an RTR recorder having no high-speed driveis used in playing back still pictures, the recorded data are preferablyarranged (to be re-recorded to remove fragmentation) as needed.

When the latter format 1) shown in FIGS. 10A to 10C is adopted as theformat that allows to continuously record a plurality of pieces of stillpicture information, a plurality of VOBs are grouped, as shown in FIG.3C, to belong to different groups of VTTs (video titles) 1407 and 1408.

The recording format shown in FIGS. 10A to 10L can record at least twostill pictures at neighboring locations on the information storagemedium (optical disc, 1001), and can continuously record a plurality ofstill pictures in general. For this reason, for example, when aplurality of still pictures sensed by a digital camera are recorded onthe information storage medium (optical disc 1001) at one time, apractical effect and feature can be obtained, i.e., quick recording canbe attained.

In addition, the recording format that can record a plurality of stillpictures in a VOB has the following practical effects.

In the conventional recording format for a plurality of still picturessensed by a digital camera, still pictures are divisionally recorded oneby one in different data files. When still pictures are divisionallyrecorded in different files, neither image sensing order informationamong still pictures nor grouping information among still pictures areavailable. By contrast, a negative film (or a positive film prepared asneeded) is available in case of a photographic film. For this reason,when a specific still picture is to be designated upon making anadditional print, a still picture to be printed can be found by a searchon the negative film in the photographing order.

In an information recording/playback apparatus (video recorder) forrecording video information shown in FIG. 19, information of videoobject 1632 for picture objects recorded on the information storagemedium (optical disc 1001) is read, and still pictures can be displayedon the screen in the allocation order of VOBUs 1642 to 1644 like apositive film shown in FIG. 11. For example, a still picture at the leftend in FIG. 11 expresses information of VOBU 1642, and the central stillpicture expresses information of VOBU 1643. The still pictures shown inFIG. 11 can be moved to the right or left on the screen, and the userdesignates a still picture to be edited (or to be hard-copied). Unlikevideo objects 1012, still picture information designates an individualstill picture using the display shown in FIG. 11. (In video objects1012, the video information range to be edited is designated by thedisplay or presentation time.)

The data structure in video object information that pertains to stillpicture information will be explained below. Video object information(or AVFIT) shown in FIG. 1F is divided into a management informationfield (M_AVFIT in FIG. 8) that pertains to general video information,and a management information field (S_AVFIT in FIG. 8) that pertains tostill picture information. FIG. 12 shows the data structure in thelatter management information field (S_AVFIT) that pertains to stillpicture information.

The still picture AV file information table (S_AVFIT) contained innavigation data RTR_VMG shown in FIG. 8 contains still picture AV fileinformation table information (S_AVFITI), still picture VOB streaminformation (S_VOB_STI#1 to S_VOB_STI#n), still picture AV fileinformation (S_AVFI), still picture additional audio stream information(S_AA_STI#l to S_AA_STI#m), and still picture additional audio fileinformation (S_AAFI), as shown in the left column in FIG. 12.

The still picture AV file information (S_AVFI) contains VOB information(or S_AVFI general information S_AVFI_GI) 1721 for picture objectsmanagement information, search pointer #1 (or still VOB groupinformation search pointer S_VOGI_SRP#1) 1726 of VOB information forpicture objects, . . . , #i (S_VOGI_SRP#i) 1727, . . . , #k(S_VOGI_SRP#k) 1728, and VOB information #1 (or still picture VOB groupinformation S_VOGI#1) 1731 for picture objects, . . . , #i (S_VOGI#i)1732, . . . , #k (S_VOGI#k) 1733, as shown in the central column in FIG.12.

VOB information #i for picture objects (or still picture VOB groupinformation S_VOGI#i) has the contents shown in the right column in FIG.12 (the same applies to VOB information #1 and information #k forpicture objects).

That is, VOB information #i for picture objects is comprised of VOBgeneral information 1736 for picture objects (or still picture VOB groupgeneral information S_VOG_GI), VOB attribute information 1737 forpicture objects, and VOBU map 1738 for picture objects (or one or morestill picture VOB entries S_VOB_ENT#).

Note that S_VOG_GI contains the number (S_VOB_Ns) of VOBs, a stillpicture VOB stream information number (S_VOB_STIN), time information(FIRST_VOB_REC_TM) indicating the recording time of the first VOB inthat VOB group, time information (LAST_VOB_REC_TM) indicating therecording time of the last VOB in that VOB group, and the start address(S_VOG_SA) of the VOB group in a still picture AV file. S_VOG_SAexpresses a relative address from the first address of S_AVFI in unitsof sectors.

On the other hand, S_VOB_ENT# includes four types (types 1 to 4), whichrespectively have the following contents:

(1) S_VOB_ENT of type 1 contains information (S_VOB_ENT_TY) indicatingthe type of VOB entry of a still picture, and information (V_PART_SZ)indicating the video part size in a still picture VOB in units ofsectors.

(2) S VOB_ENT of type 2 contains information (A_PART_SZ) that expressesthe original audio part size in a still picture VOB in units of sectors,and information (A_PB_TM) that expresses the playback time of this audiopart in units of video fields, in addition to S_VOB_ENT_TY and V_PART_SZof type 1. When the playback time of an actual audio part does not matcha boundary of video fields, data after the video field of end data ofthe audio part is discarded.

(3) S_VOB_ENT of type 3 contains number information (S_AAGN) of anadditional audio group contained in an audio stream added to a stillpicture VOB, and information (AA_ENTN) of an entry number correspondingto this sill picture VOB additional audio stream, in addition toS_VOB_ENT_TY and V_PART_SZ of type 1.

(4) S_VOB_ENT of type 4 contains S_AAGN and AA_ENTN of type 3 inaddition to S_VOB_ENT_TY, V_PART_SZ, A_PART_SZ, and A_PB_TM of type 2.

S_VOB_ENT of each of types 1 to 4 commonly contains S_VOB_ENT_TY andV_PART_SZ of type 1.

Note that each S_AA_STI (#1 to #m) in the left column in FIG. 12contains audio attribute information of an additional audio stream. Fromthis viewpoint, S_AA_STI corresponds to VOB attribute information 1737in the right column of FIG. 12.

A plurality of pieces of still picture information grouped to differentvideo objects for picture objects (VOBs for picture objects) arerecorded in video object information 1731 for picture objects to videoobject information 1733 for picture objects (or S_VOGI#1 to S_VOGI#k) inFIG. 12.

The information contents shown in the right column in FIG. 12 will bebriefly explained below.

Information 1732 contains the following information:

-   *VOB general information 1736 for picture objects (or S_VOG_GI) . .    .    -   ID information uniquely set in units of VOBs so as to designate        a specific VOB in, e.g., cell playback information (CI in FIG.        1F or S_CI in FIG. 23) 1108;

VOB type information . . . information indicating information shown inFIGS. 10A to 10L to which the VOB belongs, information indicating videoinformation (video objects 1012)/still picture information (pictureobjects 1013)/audio information (audio objects 1014) to which the VOBpertains, and the date of recording of the VOB on the informationstorage medium (optical disc 1001);

-   *VOB attribute information 1737 for picture objects . . .

attribute information such as resolution or the like of still pictureand/or attribute information of audio information,

the number of pieces of sub-picture information, recording format, andthe like;

-   *VOB Map 1738 for Picture Objects

. . . information that pertains to all still pictures included in a VOB.

Video object information 1721 for picture objects management informationcontains the following information:

the number of VOBs for picture objects contained in this AV file;

general information that pertains to VOBs contained in this AV file; andthe like.

Also, address data indicating the recording locations of a plurality ofpieces of video object information 1731 to 1733 for picture objects invideo object information 1107 shown in FIG. 1F are recorded in searchpointers 1726 to 1728 of video object information for picture objects.

The data structure in VOBU map 1738 for picture objects will beexplained below with reference to FIG. 13.

As shown in the central column of FIG. 13, the number of still picturescontained in the corresponding VOB (i.e., the number of VOBUs; or numberof such VOBs S_VOB_Ns) 1801 is stored at the beginning of VOBU map 1738for picture objects (S_VOB_ENT#). Information (1802, 1803, 1804, . . . )that pertains to each still picture (contents of a VOBU) follows in theallocation order in a VOB.

As the information (e.g., 1803) that pertains to each still picture(contents of a VOBU), information shown in the right column in FIG. 13is recorded.

Referring to FIG. 13, information 1807 of VOBU 1411 (FIG. 3E) having onestill picture information which also contains audio information isdivisionally recorded on a plurality of sectors 1431 to 1434, as shownin, e.g., FIG. 3F. Data size (V_PART_SZ and/or A_PART_SZ) 1806 for onestill picture information (VOBU) is indicated by the number of sectorsused in divisional recording.

In case of a VOBU which includes A_PCK (audio pack), as shown in FIGS.10A to 10C or FIGS. 10D to 10F, display time 1807 of one still picturemeans the playback time of audio information in a VOBU. On the otherhand, in case of a VOBU which includes no A_PCK (audio pack), as shownin FIGS. 10G to 10I, display time 1807 means the still display period ofa still image.

As information that pertains to still image information itself in a VOBUthat records one still picture information, the following information(the right column in FIG. 13) is recorded.

-   *start V_PCK address (or S_VOG_SA) 1808 in the corresponding VOBU

. . . Taking FIGS. 10A to 10L as an example, address data of V_PCKs1661, 1664, 1665, 1666, 1667, 1668, 1671, 1674, and the like located atthe start positions of VOBUs are recorded. When the ID of a VOB thatcontains a still image the user wants to watch, and the still picturenumber (VOBU number) in that VOB are designated, an optical head (notshown) directly accesses the start V_PCK address of the correspondingVOBU using this address data.

In general, as address information, the LAN (logical sector number)directly indicating the position on the information storage medium(optical disc 1001) is used, as shown in FIG. 4. However, the presentinvention is not limited to such specific address indication method, andother application examples are available. For example, as shown in FIG.9C, the address on the medium may be indicated by the number of sectors(relative address) by counting sectors in the sequence order from thefirst address of a given VOB in accordance with the sequence order ofdata.

-   *I-picture size 1809 in corresponding VOBU

. . . As has been described above with reference to FIG. 10C or FIG.10I, dummy information 1704 is recorded in a field which is short froman integer multiple of 2,034 bytes as the pack size in the data sizes ofI-pictures 1706 and 1707. Hence, when the I-picture size is known inadvance, the recording location of dummy information 1704 can bedetected, and the next location can be accessed without playing backthat location, thereby realizing high-speed playback.

-   *S_PTM (presentation starting time) 1810 of still picture (V_PCK &    SP_PCK)

. . . This information indicates the display timing of a still pictureand a sub-picture added thereto upon playback. In this embodiment, astill picture recorded in V_PCK and a sub-picture to be added to thatpicture are simultaneously displayed upon playback. S_PTM is used to setthe display timing in relation to audio information in one VOBU.

-   *First_SCR (first system clock) 1811 of still picture (V_PCK)

. . . This information means the system clock value upon creating firstV_PCK in a VOBU upon recording on the information storage medium(optical disc 1001), and is used upon executing seamless (continuous)playback.

As information that pertains to audio information in a VOBU whichrecords one still picture information, the following information isrecorded.

-   *first A_PCK address 1812 in VOBU

. . . Taking FIGS. 10A to 10L as an example, address data of, e.g.,A_PCKs 1691, 1693, 1694, 1695, 1696, 1699, 1702, and the like located atthe start positions of VOBUs are recorded. When the ID of a VOB thatcontains a still image the user wants to watch, and the still picturenumber (VOBU number) in that VOB are designated, an optical head (notshown) directly accesses the start V_PCK address of the correspondingVOBU using this address data.

As shown in FIG. 14C, in the present invention, audio information (A_PCKinformation) in one VOB can be displayed in combination with stillpicture information that belongs to another VOB. Hence, this informationis used when audio information alone in a VOB is selectively playedback.

-   *S_PTM (presentation starting time) 1813 of audio information    (A_PCK)

. . . This information indicates the output timing of audio informationupon playback. In most cases, this value matches S_PTM 1810 of a stillpicture (V_PCK & SP_PCK). A different value may be intentionally setwhen an audio is to be output a specific time (e.g., 0.5 sec) after astill picture is displayed on the screen. In this manner, thisinformation is used in timing control between the still picture displayand audio information output.

-   *E_PTM (presentation terminating time) 1814 of audio information    (A_PCK)

. . . This information indicates the output termination timing of audioinformation upon playback, and is used in timing control between thestill picture display and audio information output. In most cases, thisvalue matches S_PTM 1810 (to be described below) of a still picture(V_PCK & SP_PCK). A different value may be intentionally set when thenext still picture information begins to be displayed a specific time(e.g., 0.5 sec) after termination of the audio output.

-   *First_SCR (first system clock reference) 1815 of audio information    (A_PCK)

. . . This information indicates the system clock value upon creatingfirst A_PCK in a VOB upon recording on the information storage medium(optical disc 1001), and is used upon executing seamless (continuous)playback.

-   *Last_SCR (last system clock reference) 1816 of audio information    (A_PCK)

. . . This information indicates the system clock value upon creatinglast A_PCK in a VOB upon recording on the information storage medium(optical disc 1001), and is used upon executing seamless (continuous)playback.

The contents corresponding to A_PB_TM mentioned in the description ofS_VOB_ENT in FIG. 12 can be expressed by a pair of First_SCR andLast_SCR above.

In this manner, by recording presentation time PTM information andsystem clock reference SCR information that respectively pertain tostill picture information and audio information, video information thatbelongs to video objects 1012 shown in FIG. 1D can be used as a part ofstill picture information.

More specifically, new video object information for picture objects(S_VOB) for a still picture is defined as follows without modifyingvideo information itself that belongs to video objects 1012.

A case will be explained below wherein still pictures that change every2 sec are defined with respect to the conventional video method (videoobjects 1012). In general, since the time required for one GOP in videoinformation is 0.5 sec, one VOBU shown in FIG. 3E normally has aduration around 0.5 sec. Since 2 sec÷0.5 sec=4, the first I-pictures ofevery four VOBUs are considered as still pictures, thus settinginformation of first V_PCK address 1808 and I-picture size 1809 in aVOB, and setting the numerical values of data in the right column ofFIG. 18.

As a result, by combining and displaying still picture information andaudio information that belong to different VOBs (VOB#A and VOB#B), asshown in FIGS. 14A to 14G, only an audio part in video information thatbelongs to video objects 1012 can be output upon displaying a stillpicture, or only a scene the user likes in video information thatbelongs to video objects 1012 can be converted into a still picture andthe still picture can be displayed.

A method of displaying a plurality of still pictures will be explainedbelow.

As a method of displaying a plurality of pieces of still pictureinformation recorded on the information storage medium (optical disc1001), a method of simultaneously displaying a plurality of pictures ina given layout (still pictures to be displayed in the given layout areoften moved or replaced), as shown in FIG. 11, and a method ofdisplaying one still picture, and changing the still picture to bedisplayed at specific time intervals are available. In either method, acell and PGC information are used in the data structure, as shown inFIGS. 6 and 7, and the user can choose the display method by aninformation recording/playback apparatus (RTR video recorder) forrecording video information shown in FIG. 19.

As in video object information 1107, cell playback information (or CI)1108 shown in FIG. 1F is divided into cell playback information (M_CI)that pertains to video information, and cell playback information (S_CI)that pertains to still picture information. The cell playbackinformation (S_CI) that pertains to still picture information has astructure that can play back a still picture and audio information fromdifferent locations, and can present them together, as shown in FIGS.14A to 14G.

More specifically, as shown in FIGS. 14C to 14E, in this structure,V_PCKs 1852 and 1854, and SP_PCK 1848 used in display in a given cellcan designate still pictures (STL PCT) 1832 and 1834 in VOB#A 1821, andaudio information output from that cell can designate audio information1845 and audio information 1846 in VOB#B 1822 different from VOB#A 1821.

This structure is suitable for after recording setups for a stillpicture. For example, when still picture information sensed by a digitalcamera having no audio input function is directly recorded on theinformation storage medium (optical disc 1001), its recording result hasa structure that does not contain any A_PCK (audio pack), as shown inFIG. 10I. A case will be examined below wherein the recorded informationis played back, and comments are added to still pictures one by one by“audio input via a microphone”, “overwriting marks by handwriting”,“addition of text information by key-in”, and the like, while displayingthem on the screen, as shown in FIG. 11.

In this case, when the recording format is to be changed from thestructure that does not contain any A_PCK shown in FIG. 10I to astructure that contains A_PCK shown in FIG. 10F, re-recording must bedone on the information storage medium (optical disc 1001), resulting incumbersome processes and a long processing time.

By contrast, when additional information alone is recorded as anotherVOB 1634 on the information storage medium (optical disc 1001), as shownin FIGS. 10J to 10L, without modifying the data that does not containany A_PCK (audio pack) shown in FIG. 10I, information can be added to astill image very easily and quickly later. Upon display, VOBs 1633 and1634 in FIGS. 10G and 10J are displayed and output together like VOBs1403 to 1405 in FIG. 3D.

FIG. 15 shows the data structure in cell playback information forpicture objects (S_CI) that allows the presentation shown in FIGS. 14Ato 14G. ID information (or CI_SRP) 1873 as an identifier unique to acell is described first. Type information (or C_TY) 1880 of a celldescribed next represents:

1) identification information for identifying cell information thatpertains to video information (video objects 1012), cell informationthat pertains to a still picture (picture objects 1013), or cellinformation that pertains to only audio information (audio objects1014); and

2) identification information for identifying cell information(corresponding to the structure shown in FIG. 15) for a VOB that recordsa plurality of still pictures (the format shown in FIGS. 10D to 10L), orcell information (corresponding to the structure shown in FIG. 16) for aVOB that records only one still picture (the format shown in FIGS. 10Ato 10C).

In this way, by absorbing any differences of the recording formats thatrecord still pictures at the level of cell playback information forpicture objects (S_CI), both still and moving pictures can be playedback and displayed in a single sequence at the level of PGC shown inFIG. 7 beyond the recording format difference of VOBs, irrespective ofthe still picture information and moving picture information.

In the embodiment shown in FIG. 14A, VOB#A 1821 is designated as IDinformation 1874 of a VOB shown in FIG. 15 that records a video pack.When the user wants to display still pictures from the second one inVOB#A 1821, still picture number 2 in VOB#A 1821 is designated as stillpicture number 1875 to be displayed first in a cell. Also, incorrespondence with the embodiment shown in FIG. 14B, still picturenumber h in VOB#A 1821 is designated as still picture number 1876 to bedisplayed last in the cell.

In this manner, the cell playback information for picture objects (S_CI)directly designates a “still picture” itself.

In the embodiment show in FIG. 15, “still picture number” is designatedas a method of designating a still picture. However, the presentinvention is not limited to such specific method. For example, a stillpicture may be designated by “designating a unit (e.g., a VOBU) itselfwhere a still picture is recorded”, “designating the start address of alocation where a still picture is recorded”, “designating the sequenceorder in a VOB”, and the like. In FIG. 15, the first and last stillpictures in the cell are designated. However, in place of the abovedisplay method, the first still picture to be displayed in a cell, andthe total number of still pictures to be displayed in that cell may bedesignated.

Similarly, in FIG. 15, ID information 1877 (which designates VOB#B 1822in the embodiment shown in FIG. 14G) of a VOB that records an audiopack, and still picture number 1878 (which designates still picturenumber j in the embodiment shown in FIG. 14F) indicating the recordingdestination of the first audio information (A_PCK) to be output in acell are described.

In FIG. 15, no still picture number information indicating the recordingdestination of the last audio information (A_PCK) to be output in thecell is described. However, since the total number of still pictures tobe displayed in one cell can be detected based on still picture number1875 that indicates the first still picture to be displayed in a cell,and still picture number 1876 indicating the last still picture to bedisplayed in the cell, that still picture number information need not bedescribed.

When audio information is designated for all still pictures in FIG. 14C,the presentation time per still picture can be determined by S_PTM 1813and E_PTM 1814 of audio information shown in FIG. 13. On the other hand,when no audio information is designated for a specific VOBU, the stillpicture presentation time is set using information of presentation time1879 per still picture.

Referring to FIG. 15, 1873 to 1876 correspond to the still picture file(RTR_STO.VRO) in FIG. 2, and 1877 to 1879 correspond to the afterrecording audio file (RTR_STA.VRO) shown in FIG. 2.

A grouping and displaying method when one VOB records only one stillpicture will be explained below.

As shown in FIGS. 10A to 10C, when one VOB (video object for pictureobjects) 1631 records only one still picture, a plurality of VOBs havingstill pictures are grouped and that group is handled as part_of_title.This grouping information is recorded in part_of_titles information 1753(FIG. 8) in video title set information (RTR_VMGI) 1106 shown in FIG.1F.

The data structures in part_of_titles information 1753 that pertains tostill pictures shown in FIG. 17, and VOB map 1899 for picture objectsare similar to those in video object information (S_VOGI#) shown in FIG.12, and the VOBU map for picture objects (S_VOB_ENT#) shown in FIG. 13.

Also, the structure of the corresponding cell playback information forpicture objects (CI) shown in FIG. 16 is similar to that of S_CI shownin FIG. 15.

One embodiment of an information recording/playback apparatus (RTR videorecorder) for recording video information will be explained below.

FIG. 19 is a block diagram for explaining the arrangement in the RTRvideo recorder. In this specification, reference numerals are indicatedwithin blocks to save space.

The apparatus main body of the video recorder shown in FIG. 19 isroughly comprised of disc changer (disc drive unit) 1500 for rotatingone to be used of one or a plurality of information storage media(optical discs) 1001, and executing recording and playback of videoinformation with respect to optical disc 1001, encoder unit 1550 thatconstructs the video recording side, decoder unit 1560 that constructsthe playback side, and system controller (MPU) 1530 which incorporates aROM and RAM (semiconductor memory), and controls the operations of theapparatus main body.

Encoder unit 1550 comprises ADC (analog-to-digital converter) 1552,video encoder (V encoder) 1553, audio encoder (A encoder 1554),sub-picture encoder (SP encoder) 1555, formatter 1556, and buffer memory1557.

ADC 1552 receives an external analog video signal+external analog audiosignal from AV input 1542, or analog TV signal+analog audio signal fromTV tuner 1544. This ADC 1552 converts the input analog video signal intodigital data at, e.g., a sampling frequency=13.5 MHz and the number ofquantization bits=8. (More specifically, luminance component Y, colordifference component Cr (or Y−R), and color difference component Cb (orY−B) are respectively quantized by 8 bits.) Likewise, ADC 1552 convertsthe input analog audio signal into digital data at, e.g., a samplingfrequency=48 kHz and the number of quantization bits=16.

When an analog video signal and digital audio signal are input to ADC1552, the digital audio signal passes through ADC 1552. (A process forreducing jitter superposed on a digital signal, a process for changingthe sampling rate and the number of quantization bits, or the likewithout changing the contents of a digital audio signal may be done.)

When a digital video signal and digital audio signal are input to ADC1552, these signals pass through ADC 1552 (for these digital signals, ajitter reduction process, sampling rate change process, or the like thatdo not change their contents may be done).

When still picture information sensed by digital camera 1543 is input inaddition to the input video signals, it is directly input to V encoder1553 without the intervention of ADC 1552.

A digital video signal component output from ADC 1552 is sent toformatter 1556 via video encoder (V encoder) 1553. A digital audiosignal component output from ADC 1552 is sent to formatter 1556 viaaudio encoder (A encoder) 1554. Or a still picture signal directly inputto V encoder 1553 is sent from V encoder 1553 to formatter 1556.

V encoder 1553 has a function of converting the input digital videosignal into a digital signal compressed at variable bit rate on thebasis of the MPEG2 or MPEG1 specifications.

In digital camera 1543, still picture information is recorded in thebitmap or JPEG format. By contrast, in the present invention, a stillpicture is recorded on optical disc 1001 in the I-picture format ofMPEG2. For this purpose, in the present invention, V encoder 1553 hasformat conversion functions of “bitmap→MPEG2”, “JPEG→MPEG2”, and thelike.

A encoder 1554 has a function of converting the input digital audiosignal into a digital signal (or linear PCM digital signal) compressedat fixed bit rate on the basis of the MPEG or AC-3 specifications.

When a digital video signal (for example, a signal from a DVD videoplayer with an independent output terminal of a sub-picture signal) isinput from AV input 1542, or when a DVD video signal with such datastructure is broadcasted and is received by TV tuner 1544, thesub-picture signal component (sub-picture pack) in the video signal isinput to sub-picture encoder (SP encoder) 1555. Sub-picture data inputto SP encoder 1555 is arranged into a predetermined signal format, andis then sent to formatter 1556.

Formatter 1556 executes predetermined signal processing of the inputvideo signal, audio signal, sub-picture signal, and the like usingbuffer memory 1557 as a work area, and outputs recording data thatmatches a predetermined format (file structure) to data processor 1536.

In case of digital broadcast, a video signal is transmitted in the TS(transport stream) format of MPEG2. In general, when a video signal isrecorded on information storage medium (optical disc) 1001 in the MPEG2format, the PS (program stream) format is used. Hence, upon receivingdigital broadcast, the received signal is directly sent from TV tuner1544 to formatter 1556, which executes “TS→PS conversion”.

Standard encode process contents for creating the recording data will bebriefly explained below. More specifically, when encoder unit 1550 shownin FIG. 19 starts an encode process, parameters required for encodingvideo (main picture) data and audio data are set. Main picture data ispre-encoded using the set parameters, and optimal code amountdistribution for the selected average transfer rate (recording rate) iscalculated. Then, the main picture data is encoded based on the codeamount distribution obtained by pre-encoding. At this time, audio datais encoded simultaneously.

As a result of pre-encoding, if it is determined that the datacompression amount is insufficient (a desired video program cannot fallwithin information storage medium (optical disc) 1001 to be used), andpre-encoding can be re-done (if the source to be recorded is a sourcethat can be repetitively played back such as a video tape, video disc,or the like), main picture data is partially re-encoded, and thepreviously pre-encoded main picture data portion is replaced by there-encoded main picture data portion. With a series of processesdescribed above, the main picture and audio data are encoded, and theaverage bit rate value required for recording can be greatly reduced.

Likewise, parameters required for encoding sub-picture data are set, andencoded sub-picture data is generated.

The encoded main picture, audio, and sub-picture data are combined, andare converted into the data structure of desired video objects.

More specifically, a cell as a minimum unit of main picture data (videodata) is set, the configuration of cells that form a program chain,attributes of the main picture, sub-picture, and audio data, and thelike are set (some of such attribute data use information obtained uponencoding the respective data), and management information that containsvarious kinds of information which pertain to cells is recorded in themanagement information recording area (control information 1011 in FIG.1D or RTR.IFO in FIG. 2).

The encoded main picture, audio, and sub-picture data are segmented intopacks each having a predetermined size (2,048 bytes). Dummy packs thatcan be used in, e.g., after recording, are inserted into these packs asneeded. Note that time stamps such as PTS (presentation time stamp), DTS(decode time stamp), and the like are described in packs other thandummy packs, as needed. As for PTS of sub-picture data, a timearbitrarily delayed from PTS of main picture data or audio data in theidentical playback time band can be described.

Data cells are arranged in units of VOBUs to allow playback in the timecode order of data, thus forming a VOB consisting of a plurality ofcells.

Upon digitally copying video information from the digital output of theRTR video recorder shown in FIG. 19, since the contents of the cells,program chains, management tables, time stamps, and the like aredetermined in advance, they need not be created again.

The arrangement for reading/writing (recording and/or playing back)information from/to optical disc 1001 comprises disc drive unit (discchanger) 1500, information recording/reproducing unit 101, temporarybuffer memory 1534, data processor 1536, and system time counter (orsystem time clock; STC) 1538.

Temporary buffer memory 1534 is used to buffer a given amount of data tobe written on optical disc 1001 (data output from encoder unit 1550) viainformation recording/reproducing unit 101, and to buffer a given amountof data played back from optical disc 1001 (data input to decoder unit1560) via information recording/reproducing unit 101.

For example, when temporary buffer memory 1534 comprises a 4-Mbytesemiconductor memory (DRAM), it can buffer recording or playback datafor approximately 8 seconds at an average recording rate of 4 Mbps. Whentemporary buffer memory 1534 comprises a 16-Mbyte EEPROM (flash memory),it can buffer recording or playback data for approximately 30 seconds atan average recording rate of 4 Mbps. Furthermore, when temporary buffermemory 1534 comprises a 100-Mbyte, very small HDD (hard disc drive), itcan buffer recording or playback data for 3 minutes or more at anaverage recording rate of 4 Mbps.

Also, temporary buffer memory 1534 can also be used to temporarily storerecording information when optical disc 1001 is used up during videorecording, until optical disc 1001 is exchanged by a new disc.

When information recording/reproducing unit 101 uses a high-speedrecording/reproducing unit having a speed equal to or higher than doublespeeds, temporary buffer memory 1534 can also be used to store readoutdata exceeding a normal amount read out from the drive per unit time.When temporary buffer memory 1534 buffers readout data upon playback,even when an optical head (not shown) has caused read errors due tovibration shock or the like, playback data buffered by temporary buffermemory 1534 can be used instead, thus preventing a playback image frombeing discontinued.

If an external card slot (not shown in FIG. 19) is provided to the RTRvideo recorder, the EEPROM can be offered as an option IC card. On theother hand, if an external drive slot or SCSI interface is provided tothe RTR video recorder, the HDD can be offered as an option extensiondrive.

When a personal computer is used as a DVD video recorder by software,the free area of a hard disc drive or main memory of the personalcomputer itself can be used as temporary buffer memory 1534 shown inFIG. 19.

Under the control of system controller (MPU) [incorporating the ROM andRAM] 1530, data processor 1536 shown in FIG. 19 performs:

supply of a video information signal to be recorded from encoder unit1550 to information recording/reproducing unit 101;

transfer of a video information signal played back by informationrecording/reproducing unit 10i to another unit;

rewrite of management information (control information 1011) recorded oninformation storage medium (optical disc) 1001;

partial deletion of video information and management information(control information 1011 or RTR.IFO or RTR_VMG) as data recorded oninformation storage medium (optical disc) 1001; and the like.

System controller 1530 includes an MPU (or CPU), a ROM as an IC memorywritten with control programs and the like, and a RAM as an IC memorythat provides a work area required for executing programs.

Of the execution results of system controller 1530, the contents theuser of the RTR video recorder should know are displayed ondisplay/input panel 1548 of the RTR video recorder.

Note that the control timings of disc changer 1500, informationrecording/reproducing unit 101, data processor 1536, and encoder unit1550 and/or decoder unit 1560 by system controller (MPU) 1530 can bedetermined based on time data supplied from STC 1538 (videorecording/playback are normally executed in synchronism with time clocksfrom STC 1538, but other processes may be executed at timingsindependently of STC 1538).

Decoder unit 1560 comprises separator.1562 for separating the respectivepacks from video information with the pack structure recorded on opticaldisc 1001, memory 1563 used upon executing pack separation and othersignal processes, video decoder (V decoder) 1564 for decoding mainpicture data (the contents of video packs) separated by separator 1562,sub-picture decoder (SP decoder) 1565 for decoding sub-picture data (thecontents of sub-picture packs) separated by separator 1562, audiodecoder (A decoder) 1568 for decoding audio data (the contents of audiopacks) separated by separator 1562, video processor 1566 forappropriately mixing sub-picture data from SP decoder 1565 with videodata output from V decoder 1564, i.e., superposing sub-picture data suchas menus, highlight buttons, superimposed dialogs, and the like on mainpicture data, and outputting them, video digital-to-analog converter(V•DAC) 1567 for converting the digital video output from videoprocessor 1565 into an analog video signal, and audio digital-to-analogconverters (A•DAC) 1569 for converting the digital audio output from Adecoder 1568 into an analog audio signal.

The analog video signal (analog video information signal) output fromV•DAC 1567, and the analog audio signal output from A•DAC 1569 aresupplied to an external component (not shown; a multi-channel stereosystem having two to six channels+monitor TV or projector) via AV output1546.

OSD (On Screen Display) data output from system controller (MPU) 1530 isinput to separator 1562 in decoder unit 1560, and is then input to videoprocessor 1566 via V decoder 1564 (not decoded). The OSD data issuperimposed on main picture data, and they are supplied to an externalmonitor TV connected to AV output 1546. Thus, a warning message isdisplayed together with main picture data.

The operations of the information recording/playback apparatus (RTRvideo recorder) for recording video information shown in FIG. 19 will bedescribed below with reference to the flow charts.

The sequence for recording a plurality of still pictures on informationstorage medium (optical disc) 1001 will be described below withreference to FIG. 20.

Still picture files are continuously input from digital camera 1543 asdata (ST1).

Since each still picture file received from digital camera 1543 isnormally recorded in the JPEG or bitmap format, the input still pictureinformation is converted into I-picture data of MPEG2 at V encoder 1553(ST2).

Formatter 1556 prepares the VOBU structure with the data structure shownin FIG. 3 with respect to single still picture information, and groups aplurality of still pictures to construct a VOB (ST3).

Parallel to the aforementioned processes, informationrecording/reproducing unit 101 reproduces all pieces of controlinformation 1011 (RTR.IFO/RTR_VMG) recorded on optical disc 1001, andsaves the reproduced contents in the internal RAM of system controller1530 (ST4).

System controller 1530 obtains information of allocation map table 1105from the contents of control information 1011 saved in its internal RAM,and searches for the location of unrecorded area 1460 (FIG. 4) (ST5).

After that, system controller 1530 sends control information toformatter 1556, data processor 1536, and informationrecording/reproducing unit 101, and controls informationrecording/reproducing unit 101 to record a VOB having a plurality ofpieces of still picture information on unrecorded area 1460 (ST6).

During recording, system controller 1530 monitors the recording state,and checks if the VOB is successfully recorded on optical disc 1001(ST7). If trouble has occurred during recording, the processes in stepsST4 to ST6 are repeated.

If the VOB is successfully recorded on optical disc 1001, systemcontroller 1530 prepares VOBU map 1738 in FIG. 12 (or VOB map 1899 inFIG. 17) on the basis of address information recorded on optical disc1001 (ST9). Finally, VOBU map 1738 (or VOB map 1899) prepared in systemcontroller 1530 is additionally recorded in control information 1011(RTR.IFO/RTR_VMG) on optical disc 1001 using informationrecording/reproducing unit 101 (ST10).

The playback sequence of still picture information containing audioinformation will be described below with the aid of FIG. 22.

As in steps ST4 and ST5 in FIG. 20, information recording/reproducingunit 101 reproduces all pieces of control information 1011(RTR.IFO/RTR_VMG) recorded on optical disc 1001, and saves thereproduced contents in the internal RAM of system controller 1530(ST11).

System controller 1530 obtains information of playback controlinformation 1021 (CI) from the contents of control information 1011saved in its internal RAM, and interprets the obtained information as tothe manner of reproduction (ST12).

After that, system controller 1530 searches for a program of informationto be reproduced from PGC control information 1103 (PGCI) saved in itsinternal RAM, and extracts a cell or cells contained in that PGCinformation (ST13).

Furthermore, system controller 1530 extracts the recording address ofthe VOB to be reproduced on optical disc 1001 from video objectinformation 1107 (AVFIT) or part_of_titles information 1753 (FIG. 8) invideo title set information 1106 (RTR_VMGI) saved in its internal RAM(ST14).

The playback sequence for playing back still picture information fromVOB#A and presenting audio information recorded in VOB#B simultaneouslywith the still picture upon playback, as shown in FIGS. 14A to 14G, willbe explained.

An optical head (not shown) in information recording/reproducing unit101 accesses VOB#B recorded on optical disc 1001 on the basis of acontrol signal from system controller 1530 to reproduce its information,and temporarily saves audio information for a plurality of stillpictures in that reproduced information in memory 1563 (FIG. 19) (ST18).

The optical head in information recording/reproducing unit 101 thenaccesses the information recording position of VOB#A recorded on opticaldisc 1001 to reproduce still picture information in VOB#A (ST16).Finally, AV output 1546 simultaneously outputs (displays) audioinformation in VOB#B and still picture information in VOB#A (ST17).

As described above, the method of simultaneously reproducing only audioinformation for a plurality of still pictures or only still pictureinformation, saving the reproduction result in memory 1562,simultaneously reproducing the remaining information, and outputting(displaying) the reproduction results at the same time is used. Withthis method, compared to a method of reproducing still pictureinformation and audio information in units of still pictures, thefrequency of access of the optical head can be greatly reduced, thusallowing a seamless, continuous output (free from any wait time uponchanging the still picture to be displayed, or free from any interruptof audio information). This is a great feature of this invention.

In FIG. 22 described above, after audio information in VOB#B isreproduced, still picture information in VOB#A is reproduced. However, amodification may be made without departing from the scope of the presentinvention (e.g., the reproduction order may be replaced).

In the recording format shown in FIGS. 10A to 10L, a pair of stillpicture information and audio information are saved in a VOBU. However,the present invention is not limited to such specific format. Thecontents of the present invention can be applied as long as the scope ofthe invention is implemented.

For example, in case of a recording format in which V_PCKs for aplurality of still pictures may be allocated in one VOB or in the firsthalf of one PTT, and A_PCKs for a plurality of still pictures areallocated in the second half, the positions of V_PCK and A_PCK of astill image of a given number are separated from each other oninformation storage medium (optical disc) 1001. Hence, even when stillpicture information (V_PCK information) and audio information (A_PCKinformation) with an identical still picture number in one VOB arereproduced in turn, optical head access is required.

Therefore, when a plurality of pieces of still picture information arereproduced from picture objects 1013 with the recording format in whichV_PCKs for a plurality of still pictures may be allocated in one VOB orin the first half of one PTT, and A_PCKs for a plurality of stillpictures are allocated in the second half, either V_PCK or A_PCKinformation for a plurality of still pictures is read in advance andsaved in memory 1563, the remaining information is then reproduced, andthe reproduction results can be simultaneously output (displayed),according to the sequence of the present invention.

As another embodiment of the present invention, a method of additionallyrecording additional information for a still picture by after recordingwill be explained below with reference to FIG. 21. Information to beadded by after recording forms a group (another VOB or PTT) differentfrom that of original still picture information, and the additionalinformation and still picture information are synthesized and output(displayed) by the method shown in FIGS. 14A to 14G.

Referring to FIG. 21, steps ST 11 to ST14 are the same as those in FIG.22. The optical head in information recording/reproducing unit 101accesses a VOB recorded on optical disc 1001 to reproduce itsinformation, and the display contents shown in FIG. 11 are supplied toAV output 1546 (ST18). Additional information input by the user whileobserving the display screen is received, and a plurality of stillpictures are grouped by formatter 1556 on the basis of the inputinformation to construct a VOB or PTT (ST19).

Finally, VOB information constructed by formatter 1556 is recorded onoptical disc 1001 (ST20).

FIG. 23 is a view for explaining the data structure of navigation data(RTR_VMG) shown in FIG. 8. This RTR_VMG corresponds to controlinformation 1101 and information 1021 in FIG. 1E, and corresponds tocontrol information (RTR.IFO) 1011 in the file structure shown in FIG.2.

Of this navigation data RTR_VMG, user defined PGC information tableUD_PGCIT is comprised of user defined PGC information table information(UD_PGCITI), one or more user defined PGC information search pointers #1to #n (UD_PGCI_SRP#1 to UD_PGCI_SRP#n), and one or more pieces of userdefined PGC information #1 to #n (UD_PGCI#1 to UD_PGCI#n) correspondingin number to these search pointers.

Each user defined PGC information (one of UD_PGCI#l to UD_PGCI#n) or PGCinformation #i (PGCI#i) having contents corresponding to original PGCinformation (ORG_PGCI) is composed of PGC general information (PGC_GI),one or more pieces of program information #1 to #m (PGI#1 to PGI#m), oneor more cell information search pointers #1 to #n (CI_SRP#1 toCI_SRP#n), and one or more pieces of cell information #1 to #n (CI#l toCI#n) corresponding in number to these search pointers.

Each cell information search pointer (one of CI_SRP#1 to CI_SRP#n)contains the start address (CI_SA) of corresponding cell information,and each cell information (one of CI#l to CI#n) contains movie cellinformation (M_CI) or still picture cell information (S_CI).

Note that RTR_VMGI in FIG. 23 corresponds to video title set information1106 in FIG. 1F, M_AVFIT and S_AVFIT in FIG. 23 correspond to videoobject information 1107 in FIG. 1F, and ORG_PGCI and UD_PGCIT in FIG. 23correspond to PGC control information 1103 in FIG. 1F.

On the other hand, PGCI#i in FIG. 23 corresponds to PGC controlinformation 1103 in FIG. 1F, and CI# in FIG. 23 corresponds to cellplayback information 1108 in FIG. 1F.

FIG. 24 is a view for explaining the contents of still picture cellinformation (S_CI) in FIG. 23. S_CI contains still picture cell generalinformation (S_C_GI), and one or more pieces of still picture cell entrypoint information #1 to #n (S_C_EPI#1 to S_C_EPI#n). Note that S_CI inFIG. 24 corresponds to cell playback information 1108 in FIG. 1F.

FIG. 25 is a view for explaining the contents of still picture cellgeneral information (S_C_GI) in FIG. 24.

This S_C_GI contains a cell type (C_TY) which describes the type ofcell, the still picture VOB group information search pointer number(S_VOGI_SRPN) of the VOB group used by this cell, the number (C_EPI_Ns)of pieces of cell entry point information in this cell, the startaddress (S_S_VOB_ENTN) of the still picture VOB entry number of thiscell, and the end address (E_S_VOB_ENTN) of the still picture VOB entrynumber of this cell.

Note that S_S_VOB_ENTN in FIG. 25 corresponds to still picture number1875 in VOB in FIG. 15, and E_S_VOB_ENTN in FIG. 25 corresponds to stillpicture number 1876 in a VOB in FIG. 15.

FIG. 26 is a view for explaining the contents of each still picture cellentry point information (S_C_EPI) in FIG. 24. This S_C_EPI has twodifferent types (type 1 and type 2).

S_C_EPI of type 1 contains an entry point type (EP_TY) that describesthe type of entry point, and still picture VOB entry number(S_VOB_ENTN).

S_C_EPI of type 2 further contains primary text information (PRM_TXTI)in addition to EP_TY and S_VOB_ENTN. This PRM_TXTI can record a commentand other information associated with the corresponding still picture.

Note that S_VOB_ENTN in FIG. 26 is number information which specifieseach of one or more still picture VOB entries S_VOB_ENT# (correspondingto VOBU map 1738 for picture objects in FIGS. 12 and 13, or VOB map 1899for picture objects in FIG. 17).

FIG. 27 is a view for explaining the contents of still pictureadditional audio file information (S_AAFI) in FIG. 12.

This S_AAFI contains still picture additional audio file informationgeneral information (S_AAFI_GI), one or more still picture additionalaudio group information search pointers #1 to #n (S_AAGI_SRP#1 toS_AAGI_SRP#n), and a plurality of pieces of still picture additionalaudio group information #1 to #n (S_AAGI#l to S_AAGI#n) corresponding innumber to these search pointers.

Each still picture additional audio group information (one of S_AAGI#lto S_AAGI#n) contains still picture additional audio group generalinformation (S_AAG_GI), and one or more additional audio entries #1 to#n (AA_ENT#1 to AA_ENT#n).

FIG. 28 is a view for explaining the contents of S_AA_GI generalinformation (S_AAG_GI) in FIG. 27.

This S_AAG_GI contains the number (AA_ENT_Ns) of additional audioentries, the still picture additional audio stream information number(S_AA_STIN), and the start address (S_AAG_SA) of AAG in a still pictureadditional audio file.

Note that AA_ENT_Ns in FIG. 28 assumes a value corresponding to number1801 of still pictures in a VOB in FIG. 13 or number 1901 of stillpictures in PTT in FIG. 18.

S_AAG_SA in FIG. 28 corresponds to the first still picture address(first still picture information 1802 in a VOB or first V_PCK address.1808 in a VOBU in FIG. 13; or first still picture information 1902 in aPTT or first V_PCK address 1908 in a VOB in FIG. 18).

FIG. 29 is a view for explaining the contents of the additional audioentry (AA_ENT) shown in FIG. 27.

This AA_ENT contains an additional audio type (AA_TY) that describes thetype of additional audio (e.g., normal one or tentatively created one),the size (AA_SZ) of an additional audio stream, and the playback time(AA_PB_TM) of the additional audio stream.

Note that AA_SZ in FIG. 29 assumes a value corresponding to thedifference between the A_PCK address of the current additional audio(first A_PCK address 1812 in a VOBU in FIG. 13 or first A_PCK address1912 in a VOB in FIG. 18), and the A_PCK address of the next additionalaudio (1812 in FIG. 13 or 1912 in FIG. 18).

On the other hand, AA_PB_TM in FIG. 29 corresponds to the differenceobtained by subtracting audio S_PTM 1813 from audio E_PTM 1814 in FIG.13 (or the difference obtained by subtracting audio S_PTM 1913 fromaudio E_PTM 1914 in FIG. 18).

FIG. 30 is a view for explaining the contents of still picture VOB groupgeneral information (S_VOG_GI) shown in FIG. 12.

This S_VOG_GI contains the number (S_VOB_Ns) of still pictures thatdescribes the number of video parts in the corresponding VOB group, thenumber (S_VOB_STIN) of pieces of still picture VOB stream information,the e time (FIRST_VOB_REC_TM) when the first VOB in that VOB group wasrecorded, the time (LAST_VOB_REC_TM) when the last VOB in that VOB groupwas recorded, and the start address (S_VOG_SA) of that VOB group in astill picture AV file.

Note that S_VOB_Ns in FIG. 30 has a value corresponding to number 1901of still pictures in a VOB in FIG. 13 or number 1901 of still picturesin a PTT shown in FIG. 18.

Also, S_VOG_SA in FIG. 30 corresponds to the first still picture address(first still picture information 1802 in a VOB or first V_PCK address1808 in a VOBU in FIG. 13; or first still picture information 1902 in aPTT or first V_PCK address 1908 in a VOB in FIG. 18).

FIG. 31 is a view for explaining the first example (type 1) of thecontents of still picture VOB entry (S_VOB_ENT) in FIG. 12.

This S_VOB_ENT of type 1 contains a still picture VOB entry type(S_VOB_ENT_TY) that describes the type of still picture VOB entry, andthe size (V_PART_SZ) of the corresponding still picture video part.

Note that S_VOB_ENT_TY contains information MAP_TY that describes thetype of S_VOB_ENT, information TE that describes whether thecorresponding VOB is normal or tentatively erased (temporarily erased),and information SPST_Ns that describes the number of sub-picture streamscontained (if it is zero, no streams are contained).

On the other hand, V_PART_SZ describes the size of the video part inthat VOB in units of sectors.

This V_PART_SZ corresponds to the difference between the address (1808in FIG. 13) of the first V_PCK in the current still picture VOBU, andthe address (1812 in FIG. 13) of the first A_PCK in the current stillpicture VOBU.

Or this V_PART_SZ corresponds to the difference between the address(1908 in FIG. 18) of the first V_PCK in the current still picture VOB,and the address (1912 in FIG. 18) of the first A_PCK in the currentstill picture VOB.

FIG. 32 is a view for explaining the second example (type 2) of thecontents of still picture VOB entry (S_VOB_ENT) in FIG. 12.

This S_VOB_ENT of type 2 contains A_PART_SZ that indicates the size ofthe audio part which is originally attached to the still picture VOB inunits of sectors, and A_PB_TM that indicates the playback time of theaudio part in units of video fields, in addition to S_VOB_ENT_TY andV_PART_SZ of type 1 shown in FIG. 31.

When the playback time of an actual audio part does not match a boundaryof video fields, data after the video field of end data of the audiopart is discarded.

Note that A_PART_SZ corresponds to the difference between the firstA_PCK address (1812 in FIG. 13) in the current VOBU, and the first V_PCKaddress (1808 in FIG. 13) in the next VOBU.

Or A_PART_SZ corresponds to the difference between the first A_PCKaddress (1912 in FIG. 18) in the current VOB, and the first V_PCKaddress (1908 in, FIG. 18) in the next VOB.

On the other hand, A_PB_TM corresponds to the difference between currentS_PTM 1810; FIG. 13 (or current S_PTM 1910; FIG. 18), and next S_PTM1810; FIG. 13 (or next S_PTM 1910; FIG. 18).

Or A_PB_TM corresponds to the difference between S_PTM 1813 and E_PTM1814 in FIG. 13 (or the difference between S_PTM 1913 and E_PTM 1914 inFIG. 18).

FIG. 33 is a view for explaining the third example (type 3) of thecontents of still picture VOB entry (S_VOB_ENT) in FIG. 12.

This S_VOB_ENT of type 3 contains the still picture additional audiogroup number (S_AAGN) and additional audio entry number (AA_ENTN) inaddition to S_VOB_ENT_TY and V_PART_SZ of type 1 shown in FIG. 31.

Note that S_AAGN indicates the number of additional audio group thatcontains the additional audio stream of the corresponding VOB. ThisS_AAGN corresponds to ID information 1877 of a VOB having A_PCK in FIG.15.

On the other hand, AA_ENTN indicates the number of additional audioentry corresponding to the additional audio stream of the correspondingVOB. This AA_ENTN corresponds to still picture number 1878 in a VOB thatcontains A_PCK of the first still picture in a cell in FIG. 15.

FIG. 34 is a view for explaining the fourth example (type 4) of thecontents of still picture VOB entry (S_VOB_ENT) in FIG. 12.

This S_VOB_ENT of type 4 has contents that combine S_VOB_ENT_TY andV_PART_SZ of type 1 shown in FIG. 31, A_PART_SZ and A_PB_TM of type 2shown in FIG. 32, and S_AAGN and AA_ENTN of type 3 shown in FIG. 33.

In entries S_VOB_ENT of types 1 to 4 shown in FIGS. 31 to 34, the samefield names (S_VOB_ENT_TY and the like) have the same contents.

FIG. 35 is a view for explaining the relationship between the originalPGC information (ORG_PGCI in FIG. 8 or 23) and still picture video file(RTR_STO.VRO in FIG. 2) when only still picture VOBs are recorded.

In an original PGC where only still picture VOBs are recorded, the PGCIconsists of a sequence of cells, and each cell corresponds to a stillpicture VOB group. Still picture VOB group is introduced to reduce thenavigation data size associated with each still picture VOB, consideringwhen a huge number of still picture VOBs are recorded. However, a cellis unable to refer to both movie VOB and still picture VOB at the sametime. Therefore, if a movie VOB and a still picture VOB is recordedalternatively, a still picture VOB group may contain only one stillpicture VOB.

Assume that still picture VOB group information S_VOGI#2 in FIG. 35corresponds to VOBs 1631 to 1633 in FIGS. 10A to 10L.

Under this assumption, for example, VOBU 1641 in FIG. 10B, VOBU 1644 inFIG. 10E, and VOBU 1646 in FIG. 10H are contained in S_VOGI#2. The videopart in still picture VOB group #2 in FIG. 35 corresponds to packs 1661to 1663 and 1681 in FIG. 10C, pack 1665 in FIG. 10F, or packs 1668 to1670 and 1683 in FIG. 10I.

Also, assume that S_VOGI#2 in FIG. 35 corresponds to VOB#A in FIG. 14A.

Under this assumption, for example, still picture number 2 of VOBU 1862in FIG. 14B corresponds to VOB entry number 2 of S_VOGI#2, packs 1852,1848, and 1862 of still picture 1832 in FIG. 14C correspond to centralvideo and audio parts of the RTR_STO.VRO file in FIG. 35, and pack 1853of still picture 1833 in FIG. 14C corresponds to a trailing video partof the RTR_STO.VRO file.

FIG. 36 is a view for explaining the relationship between the originalPGC information (ORG_PGCI) and still picture additional audio part(RTR_STA.VRO in FIG. 2).

VOB entry contains access information to the associated video part andthe audio part both of which are recorded in the RTR_STO.VRO file. Theaudio part is recorded immediately after the associated video part. Whenan additional audio part associated with a video part is recorded inRTR_STA.VRO file, an additional audio entry is described in data fieldsother than the VOGI, and a link from the VOB entry to the additionalaudio entry is described in the VOB entry.

Assume that additional audio file RTR_STA.VRO in FIG. 36 corresponds toVOB#B in FIG. 14G.

Under this assumption, for example, the arrow from A_PCKs 1865 and 1866in FIG. 14D to A_PCKs 1865 and 1866 in FIG. 14E corresponds to that froma VOB entry in S_VOGI#2 in FIG. 36 to its right neighboring additionalaudio entry.

In this case, paying attention to the arrow of A_PCK 1866, A_PCK 1866 inFIG. 14E corresponds to the central audio part of RTR_STA.VRO in FIG.36, and still picture number h+j−2 in FIG. 14F constructs a partcorresponding to A_PCK 1866 of the additional audio entry in FIG. 36.

The information parts (the VOB entry and additional audio entry in FIG.36) connected by the arrow can be linked using cell playback information1108 in FIG. 1F or S_CI in FIG. 24.

When the central audio part in the RTR_STA.VRO file in FIG. 36 is audioinformation of after recording, A_PCK 1866 in FIG. 14E corresponding tothis audio part can be constructed using dummy pack DM_PCK shown in FIG.3F.

FIG. 37 is a view for explaining an example of the structure of originalPGC information (ORG_PGCI in FIG. 8 or 23) that contains still pictureVOBs (RTR_STO.VRO file) and movie VOBs (RTR_MOV.VRO file).

Assume that program #1 of PGCI#1 in FIG. 37 corresponds to VTS 1762 inFIG. 9E, S_VOGI#1 and S_VOGI#2 correspond to VOB#D 1774 and VOB#E 1775in FIG. 9F, and M_VOBI#l and M_VOBI#2 correspond to VOB#A 1771 and VOB#B1772 in FIG. 9F.

Under this assumption, picture object 1013 in FIG. 9F constructs thecontents (video and audio parts) of the RTR_STO.VRO file in FIG. 37, andvideo object 1012 in FIG. 9F constructs the contents (VOB#1, VOB#2, . .. ) of the RTR_MOV.VRO file in FIG. 37.

Referring to FIG. 37, cell# in PGCI and VOB entries in S_VOGI# can belinked using, e.g., S_S_VOB_ENTN and E_S_VOB_ENTN in FIG. 25.

On the other hand, the logical addresses of the video or audio part inthe RTR_STO.VRO file, and VOB numbers designated by VOB entries inS_VOGI# can be linked using the relationships shown in, e.g., FIGS. 4and 5.

Time map TMAP in M_VOBI# in FIG. 37 will be explained below.

Movie AV file information table M_AVFIT in FIG. 8 or 23 contains movieAV file information general information (M_AVFI_GI), one or more movieVOB information search pointers (M_VOBI_SRP#1 to M_VOBI SRP#n), and oneor more pieces of movie VOB information (M_VOBI#l to M_VOBI#n)corresponding in number to these search pointers (not shown).

Each M_VOBI#contains movie VOB general information (M_VOBI_GI), seamlessinformation (SMLI), audio gap information (AGAPI), and time mapinformation (TMAPI) (not shown).

This TMAPI is used upon executing special playback (e.g., cell playbackin the order unique to the user using user defined PGC) and time search.

TMAPI contains time map general information (TMAP GI), one or more timeentries (TMENT#1 to TM_ENT#r), and one or more VOBU entries (VOBU_ENT#1to VOBU_ENT#q) (not shown).

Each VOBU entry contains information that pertains to the size andplayback time of each VOBU. The VOBU size is indicated in units ofsectors (2 kbytes or 2,048 bytes), and the playback time is indicated inunits of video fields ( 1/60 sec per field in NTSC; 1/50 sec per fieldin PAL).

Since the VOBU size is indicated in units of sectors, as describedabove, each VOBU can be accessed using an address in units of sectors.

Each VOBU entry contains reference picture size information 1STREF_SZ,VOBU playback time information VOBU_PB_TM, and VOBU size informationVOBU_SZ (not shown).

Note that VOBU_PB_TM expresses the playback time of the VOBU of interestin units of video fields. On the other hand, reference picture sizeinformation 1STREF_SZ expresses the size of the first reference picture(corresponding to I-picture of MPEG) of that VOBU in units of sectors.

On the other hand, each time entry contains address information(VOBU_ADR) of the corresponding VOBU, and time difference information(TM_DIFF) (not shown). This time difference information indicates thedifference between the playback time designated by a time entry, and theplayback start time of the VOBU.

Assuming that the time interval (time unit TMU) between two successivetime entries is 10 sec, this time entry interval corresponds to, e.g.,600 fields in NTSC video.

Normally, the “time interval between neighboring VOBUs” is expressed bythe number of fields in the VOBU entry. As another method, “count valuefrom a given VOBU to the next VOBU by a clock counter” may be used toexpress the “time interval between neighboring VOBUs”.

For example, the “time interval between neighboring VOBUs” can beexpressed by the “difference value between the value of presentationtime stamp PTS at the start position of one VOBU and the value of PTS atthe start position of the immediately succeeding VOBU”.

In other words, “the time interval in a specific unit can be expressedby the difference value of the clock counter in that unit”.

Time map generation information TMAP_GI includes TM_ENT Ns indicatingthe number of time entries in that time map information, VOBU_ENT_Nsindicating the number of VOBU entries in that time map information, timeoffset TM_OSF for that time map information, and address offset ADR_OFSof that time map information (not shown).

When a value (10 seconds or equivalent) corresponding to 600 fields inNTSC video (or 500 fields in PAL video) is used as time unit TMU, timeoffset TM_OSF is used to represent the time offset within TMU.

When the VOBU size is expressed by the number of sectors, address offsetADR_OFS is used to indicate a file pointer from the beginning of an AVfile.

Time entry TM_ENT includes VOBU_ENTN indicating the number of thecorresponding VOBU entry, TM_DIFF indicating the time difference betweenthe playback start time of VOBU designated by the time entry, and thecalculated playback time, and VOBU_ADR indicating the target VOBUaddress (not shown).

When time unit TMU is expressed by 600 fields in NTSC (or when time unitTMU is expressed by 500 fields in PAL), the “calculated playback time”with respect to time entry #j is given by TMU×(j−1)+TM_OSF.

On the other hand, VOBU_ADR indicates the target VOBU address by thetotal size of VOBUs preceding the VOBU of interest when the VOBU size isexpressed in units of sectors.

In the aforementioned data structure, in order to start playback fromthe middle of a certain VOBU, that access point must be determined. Thisaccess point is assumed to be a time entry point.

This time entry point is located at a position separated from theposition indicated by movie address information of the VOBU by the timedifference indicated by time difference information TM_DIFF in timeentry TM_ENT. This time entry point serves as a special presentationstart point (or time search point) indicated by time map informationTMAPI.

Cell# in PGCI in FIG. 37 and time map TMAP in M_VOBI# can be linked inthe same manner as S_VOGI#.

FIG. 37 illustrates a case that a video field corresponding to thepresentation start time is in the middle of VOBU#k. In order to displaya sequence of video fields from a video field specified by thepresentation start time, the VOBU data from the beginning need to beinput to the decoder. This is because the decoder need to decode all ofthe reference video fields which have presentation time earlier than thepresentation start time, although the decoded fields should not bedisplayed. When the decoding reaches to the video field corresponding tothe presentation start time, the decoder should start display of thevideo pictures. This capability to start display exactly at the videofield corresponding to the presentation start time is recommended.

FIG. 38 is a view for explaining a case wherein user defined PGCInformation (FIG. 6) refers to a still picture VOB group.

A user defined PGC may include two types of cells, each of which refersto a movie VOB or a still picture VOB group, respectively. FIG. 38 showsan example of user defined PGC which refers to still picture VOB. In thefigure, cell#1 in the user defined PGC refers to still picture VOB group#2. Although the cell#2 in the original PGC refers to the whole stillpicture VOB group #2 by specifying the first still picture VOB numberand the last still picture VOB number in the still picture VOB group,the cell#1 in the user defined PGC refers to only a still picture VOB inthe VOB group by specifying the second still picture VOB as the firststill picture VOB number and the last still picture VOB number.

Assume that PGCI in FIG. 38 corresponds to PGC (or PGCI) 1446 in FIG.3H. In this case, cell#1 and cell#2 in PGCI in FIG. 38 correspond tocells 1441 and 1442 in FIG. 3G. On the other hand, the first video partin the RTR_STO.VRO file in FIG. 38 corresponds to a cluster of V_PCK1421 and SP_PCK 1422 in FIG. 3F. Furthermore, a video part that followsthe first video part corresponds to a cluster of A_PCK 1423 and DM_PCK1424 in FIG. 3F.

The characteristic features of the respective embodiments of the presentinvention will be summarized below.

*] One VOB or PTT can contain a plurality of pieces of still pictureinformation.

*] Upon recording a plurality of still pictures, one VOB cancontinuously record at least two pieces of still picture information inan unrecorded area.

*] Cell information (S_CI) can designate a plurality of pieces ofcontinuous still picture information.

The effects of these three “*”s are common to the respectiveembodiments.

More specifically, a high-performance digital camera can record severalthousand or several ten thousand still pictures. Upon transferring datato an optical disc, the data are preferably grouped and recorded on theoptical disc in units of a plurality of still pictures, thus allowingeasy processing and attaining short transfer time.

A high-performance digital camera can record several thousand or severalten thousand still pictures. When VOB information is prepared byconstructing a VOB for each still image, management information has ahuge size. The method of the present invention can greatly reduce themanagement information size.

Furthermore, since each still picture information forms a different filein the digital camera, management and search processes are cumbersome.In the present invention, since still pictures are grouped in units of aplurality of pictures, management and search processes are easy.

Since each still picture information forms a different file in thedigital camera, the contents of a still picture cannot be confirmedunless each file is opened. In the present, invention, the user canconfirm contents as if he or she checked a positive film (or negativefilm) of photographs, as shown in FIG. 11, by grouping still pictures inunits of a plurality of pictures.

Furthermore, video information that stretches across a plurality ofvideo frames is recorded in units of VOBs. When a plurality of stillpicture information are recorded in units of VOBs, video information andstill picture information can be processed in a single layer (in asingle directory level in FIG. 2). For example, cells of both videoinformation and still picture information can be allocated in a singlePGC, thus allowing mixed display of video information and still pictureinformation, and broadening the expression range.

*] In the embodiment of the present invention, the VOBU map (S_VOB_ENT#)or VOB map is prepared.

*] The RTR recorder has an arrangement capable of recording the VOBU mapor VOB map.

The effects of these two “*”s are common to the respective embodiments.

The user can directly access a still picture he or she wants to watchusing the VOBU map or VOB map that records information such as recordingaddresses in units of still pictures, and the access speed fordisplaying a plurality of still pictures can be greatly improved.

When a plurality of still pictures are to be continuously displayed,seamless display (with continuous joints among still pictures) can beachieved using presentation time information PTM and/or system clockreference information.

Furthermore, since the start addresses of V_PCK that records a stillpicture itself and A_PCK that records audio information are described atdifferent locations, high-speed access can be made if only still pictureinformation or audio information is to be played back. As a result, whenaudio information in a specific VOB is used to display still picture inanother VOB (since audio information alone can be accessed at highspeed), seamless display can be made.

*] In the present invention, cell information (S_CI) designates eachstill picture in a VOB.

For this reason, since each still picture itself can be designated uponplayback (using the VOBU map or VOB map), high-speed access can beperformed, and seamless display can be made when a plurality of stillpictures are to be displayed in turn.

Since each still picture itself can be designated upon playback,management upon playback becomes very easy. For example, upon displayinga plurality of still pictures on the screen at one time, as shown inFIG. 11, the processing to be executed becomes simple.

*] In the present invention, cell information (S_CI) can designate aplurality of pieces of still picture information in different VOBs.

For this reason, since continuous audio information in one VOB can beused upon displaying another VOB, the expression range can be broadened.

Furthermore, since continuous audio information in one VOB can be usedupon displaying another VOB, common data can be used and, hence, thedata size to be recorded on the information storage medium (optical disc1001) can be reduced. As a result, the actual data size that can berecorded per information storage medium (optical disc 1001) can begreatly increased.

By only preparing new video object information for picture objects(S_AVFIT) corresponding to the already recorded video information, theexisting video information can be used in combination with still pictureinformation without modifying video objects 1012 themselves.

*] In the present invention, cell information is reproduced, and a stillpicture is played back using VOBI.

As a consequence, since cell playback information for picture objects(S_CI) can be set independently of video object information for pictureobjects as management information of the contents of picture objects1013, the playback order can be designated irrespective of the recordingorder of still pictures on the information storage medium (optical disc1001), thus remarkably improving the degree of freedom in expression.

*] The present invention provides an apparatus which reads out stillpicture information or audio information from a memory, and cansimultaneously play back the still picture information and audioinformation.

When a plurality of pieces of still picture information in differentVOBs are to be designated, or when audio information alone for aplurality of still pictures is recorded on another area, if V_PCK,SP_PCK, and A_PCK are played back in turn in units of still pictures,the frequency of access becomes very high, and it is hard tocontinuously display a plurality of still pictures in turn (due to theinfluence of the access wait time of the optical head).

By contrast, when information contents for at least two still picturesof V_PCK, SP PCK, and A_PCK are played back at the same time, and aretemporarily saved in memory 1563, and the stored contents are displayedsimultaneously with the playback timing of the remaining information,the frequency of access of the optical head can be greatly reduced, thusallowing easy continuous display.

*] The present invention provides an after recording apparatus forrecording additional information to already recorded still pictures.

For example, when still picture information sensed by a digital camerahaving no audio input function is directly recorded on the informationstorage medium (optical disc 1001), the recording result has a structurewhich does not contain any A_PCK (audio pack), as shown in FIG. 10I. Acase will be examined below wherein the recorded information is playedback, and comments are added to still pictures one by one by “audioinput via a microphone”, “overwriting marks by handwriting”, “additionof text information by key-in”, and the like, while displaying them onthe screen, as shown in FIG. 11. In this case, when the recording formatis to be changed from the structure that does not contain any A_PCKshown in FIG. 10I to a structure that contains A_PCK shown in FIG. 10F,re-recording must be done on the information storage medium (opticaldisc 1001), resulting in cumbersome processes and a long processingtime. By contrast, when additional information alone is recorded asanother VOB 1634 on the information storage medium (optical disc 1001),as shown in FIG. 10J, without modifying the data that does not containany A_PCK (audio pack) shown in FIG. 10I, information can be added to astill image very easily and quickly later.

The characteristic features included in the system of the presentinvention will be described in more detail below.

According to the present invention, an information storage medium whichis capable of recording and playing back at least still pictureinformation, and continuously records a plurality of still pictures, ischaracterized by having a first information unit [VOBUs 1641 to 1649]having one still picture information, and a first group unit [VOBs 1632to 1634 or PTTs 1407 and 1408] which is comprised of a set of firstinformation units, and has a plurality of pieces of still pictureinformation having different contents, and recording information in thefirst group unit.

Note that the still picture information includes at least one of videoinformation [V_PCK 1664 and the like], sub-picture information (SP_PCK1682 and the like), and audio information [A_PCK 1693 and the like].

The first information unit is constructed by at least one of a VOBU(video object unit) and VOB (video object), and the first group unit isconstructed by at least one of a VOB (video object) and PTT(part_of_title).

An information recording/playback apparatus according to the presentinvention, which is capable of recording and playing back still pictureinformation on/from an information storage medium, comprises anunrecorded area detection unit [system controller 1530] for searchingfor an unrecorded area [unrecorded area 1460] on the information storagemedium, a still picture grouping unit [formatter 1556] for grouping aplurality of pieces of input still picture information, and aninformation recording/reproducing unit [informationrecording/reproducing unit 101] for recording the plurality of pieces ofgrouped still picture information on the unrecorded area of theinformation storage medium detected by the unrecorded area detectionunit. At least two pieces of still picture information [e.g., VOBUs 1642and 1643] of the plurality of pieces of grouped still pictureinformation are continuously recorded in nearby areas [e.g.,continuously recorded in extent#δ 1474] on the information storagemedium.

An information recording/playback apparatus according to the presentinvention, which is capable of recording and playing back still pictureinformation on/from an information storage medium, has a first recordingarea [picture objects 1013] for recording still picture informationitself, and a second recording area [control information 1011] forrecording management information that pertains to a still picture. Thisinformation storage medium [optical disc 1001] has a first informationunit [VOBUs 1641 to 1649] having one still picture information, and afirst group unit [VOBs 1632 to 1634 or PTTs 1407 and 1408] which iscomprised of a set of first information units, and has a plurality ofpieces of still picture information having different contents. Stillpicture information is recorded on the first recording area in the firstgroup unit, and a plurality of still pictures having map information[VOBU map 1738 for picture objects or VOB map 1899 for picture objects],which records management information that pertains to each still pictureinformation associated with the first information unit, are continuouslyrecorded.

An apparatus according to the present invention, which plays back aninformation storage medium capable of recording and playing back atleast still picture information, records still picture information andmanagement information that pertains to a still picture on aninformation storage medium, which has a first recording area [pictureobjects 1013] for recording still picture information itself, and asecond recording area [control information 1011] for recordingmanagement information that pertains to a still picture. Thisinformation recording/playback apparatus comprises a recording areadetection unit [system controller 1530] for detecting a location[unrecorded area 1460) where a plurality of pieces of still pictureinformation are recorded on the information storage medium, a groupingunit [formatter 1556] for forming a first group unit [VOBs 1632 to 1634or PTTs 1407 and 1408] by collecting a plurality of first informationunits [VOBUs 1641 to 1649] each having one still picture information, aninformation recording/reproducing unit [informationrecording/reproducing unit 101] for recording the grouped first groupunit on an area of the information storage medium detected by therecording area detection unit, a management information preparation unit[system controller 1530] for preparing management information [VOBU map1738 for picture objects or VOB map 1899 for picture objects] thatpertains to still picture image information in the first group unit, anda management information recording unit [informationrecording/reproducing unit 101] for recording the management informationthat pertains to still picture information, and is prepared by themanagement information preparation unit in the second recording area[control information 1011].

An information storage medium according to the present invention, whichis capable of recording and playing back at least still pictureinformation, has a first recording area [picture objects 1013] forrecording still picture information itself, and a second recording area[control information 1011] for recording management information, and thesecond recording area has a first control information recording field[video object information 1107] that records information which pertainsto a recording state of still picture information recorded in the firstrecording area on the information storage medium, and a second controlinformation recording field [playback control information 1021] thatrecords information which pertains to a playback method upon playingback still picture information recorded in the first recording area. Inthis information storage medium, minimum unit information [cell playbackinformation 1108] for playback of the still picture information isrecorded in the second control information recording field, and theminimum unit information designates a still picture itself to be playedback [still picture number 1875 in a VOB that records a video pack ofthe first still picture in a cell, and still picture number 1876 in aVOB that records a video pack of the last still picture in a cell, orstill picture number 1885 in a PTT that records the first still picturein a cell, and still picture number 1886 in a PTT that records a videopack of the last still picture in a cell].

Note that the information storage medium has a structure in which theminimum unit information [cell playback information 1108] recorded inthe second control information recording field [playback controlinformation 1021] designates a plurality of pieces of continuouslyrecorded still picture information [by designating the first and laststill picture numbers in a cell, a plurality of pieces of still pictureinformation therebetween can be designated].

On an information storage medium according to the present invention,which is capable of recording and playing back at least still pictureinformation, a plurality of pieces of still picture information arerecorded in the first recording area [video objects 1012] using a firstinformation unit [VOBUs 1641 to 1649] having one still pictureinformation, and a first group unit [VOBs 1632 to 1634 or PTTs 1407 and1408] which is comprised of a set of first information units, and has aplurality of pieces of still picture information having differentcontents. In addition, information [video object information 1107] thatpertains to a recording state of still pictures recorded in the firstgroup unit is recorded in the first control information recording field[control information 1011].

The minimum unit information [cell layback information 1108] forplayback of the still picture information and is recorded in the secondcontrol information recording field [playback control information 1021]designates a still picture [still picture numbers 1875, 1876, 1885, and1886] in a first group [VOBs 1632 to 1634 or PTTs 1407 and 1408]recorded in the first control information recording field [video objectinformation 1107] so as to play back still picture information. Also, astill picture position [still picture number j: VOBU 1828, still picturenumber h+j−2: VOBU 1829] in a second group [VOB#B 1822] different fromthe first group [VOB#A 1821] recorded in the first control informationfield is designated to simultaneously play back audio information orsub-picture information.

A playback apparatus according to the present invention has aninformation reproduction means [information recording/reproducing unit101], and an information display means [display/input panel 1548 of RTRrecorder]. The information reproduction means [informationrecording/reproducing unit 101] reproduces information that pertains toa playback method recorded in a second control information recordingfield [playback control information 1021], and then reproducesinformation that pertains to the recording state on the informationstorage medium, which is recorded in a first control informationrecording field [video object information 1107], on the basis of thereproduction result. After that, the information reproduction meansreproduces still picture information recorded in a first recording area[picture objects 1013] on the basis of the reproduction result, and theinformation display means [AV output 1546] displays the reproducedinformation.

A playback apparatus according to the present invention, comprises areproducing unit [information recording/reproducing unit 101] forsimultaneously reproducing, from an information storage medium whichrecords a plurality of pieces of still picture information in units ofgroups [VOB#A 1821, VOB#B 1822], and in which the still pictureinformation contains at least one of video information [V_PCKs 1852 and1854], sub-picture information [SP_PCK 1848], and audio information[A_PCKs 1865 and 1866], information for at least two still pictures[still picture number 2 and still picture number 3 (not shown), or stillpicture number j and still picture number j+1 (not shown)] of the videoinformation, sub-picture information, and audio information, a storageunit [memory 1563] for temporarily storing the information reproduced bythe reproducing unit, and a display unit [AV output 1546] forsimultaneously displaying information, which is obtained by reproducingthe remaining information of the video information [V_PCKs 1852 and1854], sub-picture information [SP_PCK 1848], and audio information[A_PCKs 1865 and 1866], which is not stored in the storage unit, by thereproducing unit [information recording/reproducing unit 101], and theinformation stored in the storage unit.

An after recording apparatus according to the present invention uses aninformation storage medium, which has a first information unit [VOBUs1641 to 1649] having one still picture information, and a first groupunit [VOBs 1632 to 1634 or PTTs 1407 and 1408] which is comprised of aset of first information units, and has a plurality of pieces of stillpicture information having different contents, and continuously recordsa plurality of still pictures in the first group unit. The apparatususing this medium comprises an additional information input means [AVinput 1542→ADC 1552/A encoder 1554 or SP encoder 1555] for addinginformation to each still picture information [VOBUs 1825 to 1827], atemporary storage unit [temporary buffer memory 1534] for temporarilystoring additional information added to each still picture information,an additional information synthesizing means [formatter 1556 and dataprocessor 1536] for grouping the additional information added to eachstill picture information into the first group unit [VOBs 1632 to 1634or PTTs 1407 and 1408], and an information recording means [informationrecording/reproducing unit 101] for recording synthesis informationprepared by the additional information synthesizing means on theinformation recording medium.

As described above, according to the present invention:

A) A new recording format and data structure of management information,which can process a plurality of pieces of still picture informationwhile assuring data consistency and continuity of a general videorecording format and management information in a rewritable DVD_RTR discwhich assures compatibility and continuity with DVD video disc, can beobtained.

B) A new recording format and data structure of management information,which can easily manage and search a plurality of pieces of recordedstill picture information, can be obtained.

C) An information playback apparatus, which can seamlessly andcontinuously display a plurality of pieces of still picture information(continuity upon playback) by allowing high-speed access to aninformation storage medium that records a plurality of pieces of stillpicture information, can be obtained.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. An information storage medium configured to have data recordedthereon and data reproduced therefrom by an informationrecording/reproducing apparatus, said data including control informationand audio/video data having a still picture video object, said mediumcomprising: a control information area for storing still pictureaudio/video file information for managing the still picture video objectand still picture additional audio file information, said still pictureaudio/video file information including group information of the stillpicture video object, wherein said group information includes entryinformation of the still picture video object, said entry informationincluding additional audio entry number numeral information, said stillpicture additional audio file information includes additional audioentry information for accessing an additional audio stream and numberinformation of the additional audio entry information, a data area forrecording the audio/video data is configured to include a sub-picturestream, wherein said entry information includes entry type informationcontaining number information indicating whether the sub-picture streamis included, and the information recording/reproducing apparatusaccesses the control information area to reproduce the still picturevideo object.
 2. An information recording method for recording data on amedium configured to have data recorded thereon and data reproducedtherefrom by an information recording/reproducing apparatus, said dataincluding control information and audio/video data having a stillpicture video object, said medium comprising, a control information areafor storing still picture audio/video file information for managing thestill picture video object and still picture additional audio fileinformation, said still picture audio/video file information includinggroup information of the still picture video object, wherein said groupinformation includes entry information of the still picture videoobject, said entry information including additional audio entry numbernumeral information, and said still picture additional audio fileinformation includes additional audio entry information for accessing anadditional audio stream and number information of the additional audioentry information, a data area for recording the audio/video data isconfigured to include a sub-picture stream, wherein said entryinformation includes entry type information containing numberinformation indicating whether the sub-picture stream is included, saidmethod comprising: recording the audio/video data on the data area; andstoring the control information on the control information area.
 3. Aninformation reproducing method for reproducing data from a mediumconfigured to have data recorded thereon and data reproduced therefromby an information recording/reproducing apparatus, said data includingcontrol information and audio/video data having a still picture videoobject, said medium comprising, a control information area for storingstill picture audio/video file information for managing the stillpicture video object and still picture additional audio fileinformation, said still picture audio/video file information includinggroup information of the still picture video object, wherein said groupinformation includes entry information of the still picture videoobject, said entry information including additional audio entry numbernumeral information, said still picture additional audio fileinformation includes additional audio entry information for accessing anadditional audio stream and number information of the additional audioentry information, and a data area for recording the audio/video data isconfigured to include a sub-picture stream, wherein said entryinformation includes entry type information containing numberinformation indicating whether the sub-picture stream is included, saidmethod comprising: reproducing the control information from the controlinformation area; and reproducing the audio/video data from the dataarea.
 4. An information reproducing apparatus for reproducing data fromthe medium as defined in claim 1, said apparatus comprising: a firstreproducer configured to reproduce the control information from thecontrol information area; and a second reproducer configured toreproduce the audio/video data from the data area.